diff --git a/replications/issue-1098.js b/replications/issue-1098.js
new file mode 100644
index 00000000..d5c1adfd
--- /dev/null
+++ b/replications/issue-1098.js
@@ -0,0 +1,150 @@
+/**
+ * Bug Replication for Issue #1098: transformHeader renaming and ignoring not working as expected
+ * https://github.com/mholt/PapaParse/issues/1098
+ *
+ * This script demonstrates the bug where using transformHeader to both rename headers and ignore
+ * columns by returning null causes all headers to be renamed to null.
+ *
+ * FINDINGS:
+ * - The bug is more severe than originally reported - it causes a TypeError crash
+ * - The crash occurs because stripBom() in papaparse.js tries to call charCodeAt() on null
+ * - The transformHeader function is called multiple times on the same headers
+ * - Even the workaround of returning empty string doesn't work properly
+ * - The issue affects both object-based header mapping and array-based header filtering
+ */
+
+const Papa = require('../papaparse.js');
+
+// Sample CSV data with multiple columns
+const csvData = `Code Set,Code Name,Code Value,description,extra_column1,extra_column2
+CS001,Test Code,TC123,This is a test code,Extra Data 1,Extra Data 2
+CS002,Another Code,AC456,Another test code,More Extra,Even More Extra
+CS003,Third Code,TC789,Third test code,Additional,Additional Data`;
+
+console.log('Issue #1098 Replication Script');
+console.log('==============================\n');
+
+// Header mapping as described in the issue
+const headerMap = {
+	'Code Set': 'codeSet',
+	'Code Name': 'codeName',
+	'Code Value': 'codeValue',
+};
+
+// Test Case 1: Working case - renaming headers but keeping unmapped ones
+console.log('Test Case 1: Renaming headers (keeping unmapped headers) - WORKING');
+console.log('-------------------------------------------------------------------');
+const config1 = {
+	header: true,
+	skipEmptyLines: true,
+	transformHeader: (header) => {
+		if (header in headerMap) {
+			console.log(`  Transforming "${header}" to "${headerMap[header]}"`);
+			return headerMap[header];
+		}
+		console.log(`  Keeping header "${header}" as is`);
+		return header;
+	}
+};
+
+const result1 = Papa.parse(csvData, config1);
+console.log('\nParsed data (first row):');
+console.log(JSON.stringify(result1.data[0], null, 2));
+console.log(`\nTotal rows parsed: ${result1.data.length}`);
+console.log('\n');
+
+// Test Case 2: Broken case - trying to ignore unmapped headers by returning null
+console.log('Test Case 2: Renaming headers and ignoring unmapped (returning null) - BROKEN');
+console.log('------------------------------------------------------------------------------');
+const config2 = {
+	header: true,
+	skipEmptyLines: true,
+	transformHeader: (header) => {
+		if (header in headerMap) {
+			console.log(`  Transforming "${header}" to "${headerMap[header]}"`);
+			return headerMap[header];
+		}
+		console.log(`  Returning null for header "${header}"`);
+		return null;
+	}
+};
+
+try {
+	const result2 = Papa.parse(csvData, config2);
+	console.log('\nParsed data (first row):');
+	console.log(JSON.stringify(result2.data[0], null, 2));
+	console.log(`\nTotal rows parsed: ${result2.data.length}`);
+} catch (error) {
+	console.log('\nERROR: ' + error.message);
+	console.log('Stack trace:', error.stack.split('\n').slice(0, 5).join('\n'));
+}
+console.log('\n');
+
+// Test Case 3: Using array of headers without renaming (mentioned as working in the issue)
+console.log('Test Case 3: Using array of headers without renaming - TESTING');
+console.log('---------------------------------------------------------------');
+const validHeaders = ['Code Set', 'Code Name', 'Code Value'];
+const config3 = {
+	header: true,
+	skipEmptyLines: true,
+	transformHeader: (header) => {
+		if (validHeaders.includes(header)) {
+			console.log(`  Keeping header "${header}"`);
+			return header;
+		}
+		console.log(`  Returning null for header "${header}"`);
+		return null;
+	}
+};
+
+try {
+	const result3 = Papa.parse(csvData, config3);
+	console.log('\nParsed data (first row):');
+	console.log(JSON.stringify(result3.data[0], null, 2));
+	console.log(`\nTotal rows parsed: ${result3.data.length}`);
+} catch (error) {
+	console.log('\nERROR: ' + error.message);
+	console.log('Stack trace:', error.stack.split('\n').slice(0, 5).join('\n'));
+}
+console.log('\n');
+
+// Test Case 4: Potential workaround - returning empty string instead of null
+console.log('Test Case 4: Workaround - returning empty string instead of null');
+console.log('-----------------------------------------------------------------');
+const config4 = {
+	header: true,
+	skipEmptyLines: true,
+	transformHeader: (header) => {
+		if (header in headerMap) {
+			console.log(`  Transforming "${header}" to "${headerMap[header]}"`);
+			return headerMap[header];
+		}
+		console.log(`  Returning empty string for header "${header}"`);
+		return '';  // Return empty string instead of null
+	}
+};
+
+try {
+	const result4 = Papa.parse(csvData, config4);
+	console.log('\nParsed data (first row):');
+	console.log(JSON.stringify(result4.data[0], null, 2));
+	console.log(`\nTotal rows parsed: ${result4.data.length}`);
+} catch (error) {
+	console.log('\nERROR: ' + error.message);
+	console.log('Stack trace:', error.stack.split('\n').slice(0, 5).join('\n'));
+}
+console.log('\n');
+
+// Summary
+console.log('SUMMARY');
+console.log('=======');
+console.log('\nExpected behavior:');
+console.log('- Test Case 1: Headers should be renamed according to headerMap, unmapped headers kept as is');
+console.log('- Test Case 2: Headers should be renamed according to headerMap, unmapped headers should be ignored/removed');
+console.log('- Test Case 3: Headers in validHeaders array should be kept, others should be ignored/removed');
+console.log('- Test Case 4: Workaround test - using empty string instead of null');
+console.log('\nActual behavior:');
+console.log('- Test Case 1: Works as expected');
+console.log('- Test Case 2: BUG - Causes TypeError when trying to process null headers');
+console.log('- Test Case 3: Same issue - TypeError when returning null');
+console.log('- Test Case 4: Check if empty string works as a workaround');
diff --git a/replications/issue-1098.log b/replications/issue-1098.log
new file mode 100644
index 00000000..318e915d
--- /dev/null
+++ b/replications/issue-1098.log
@@ -0,0 +1,108 @@
+Issue #1098 Replication Script
+==============================
+
+Test Case 1: Renaming headers (keeping unmapped headers) - WORKING
+-------------------------------------------------------------------
+  Transforming "Code Set" to "codeSet"
+  Transforming "Code Name" to "codeName"
+  Transforming "Code Value" to "codeValue"
+  Keeping header "description" as is
+  Keeping header "extra_column1" as is
+  Keeping header "extra_column2" as is
+  Keeping header "codeSet" as is
+  Keeping header "codeName" as is
+  Keeping header "codeValue" as is
+  Keeping header "description" as is
+  Keeping header "extra_column1" as is
+  Keeping header "extra_column2" as is
+
+Parsed data (first row):
+{
+  "codeSet": "CS001",
+  "codeName": "Test Code",
+  "codeValue": "TC123",
+  "description": "This is a test code",
+  "extra_column1": "Extra Data 1",
+  "extra_column2": "Extra Data 2"
+}
+
+Total rows parsed: 3
+
+
+Test Case 2: Renaming headers and ignoring unmapped (returning null) - BROKEN
+------------------------------------------------------------------------------
+  Transforming "Code Set" to "codeSet"
+  Transforming "Code Name" to "codeName"
+  Transforming "Code Value" to "codeValue"
+  Returning null for header "description"
+  Returning null for header "extra_column1"
+  Returning null for header "extra_column2"
+  Returning null for header "codeSet"
+  Returning null for header "codeName"
+  Returning null for header "codeValue"
+
+ERROR: Cannot read properties of null (reading 'charCodeAt')
+Stack trace: TypeError: Cannot read properties of null (reading 'charCodeAt')
+    at stripBom (/Users/dboskovic/Code/Contrib/PapaParse/papaparse.js:190:14)
+    at addHeader (/Users/dboskovic/Code/Contrib/PapaParse/papaparse.js:1234:14)
+    at Array.forEach (<anonymous>)
+    at fillHeaderFields (/Users/dboskovic/Code/Contrib/PapaParse/papaparse.js:1244:23)
+
+
+Test Case 3: Using array of headers without renaming - TESTING
+---------------------------------------------------------------
+  Keeping header "Code Set"
+  Keeping header "Code Name"
+  Keeping header "Code Value"
+  Returning null for header "description"
+  Returning null for header "extra_column1"
+  Returning null for header "extra_column2"
+  Keeping header "Code Set"
+  Keeping header "Code Name"
+  Keeping header "Code Value"
+
+ERROR: Cannot read properties of null (reading 'charCodeAt')
+Stack trace: TypeError: Cannot read properties of null (reading 'charCodeAt')
+    at stripBom (/Users/dboskovic/Code/Contrib/PapaParse/papaparse.js:190:14)
+    at addHeader (/Users/dboskovic/Code/Contrib/PapaParse/papaparse.js:1234:14)
+    at Array.forEach (<anonymous>)
+    at fillHeaderFields (/Users/dboskovic/Code/Contrib/PapaParse/papaparse.js:1244:23)
+
+
+Test Case 4: Workaround - returning empty string instead of null
+-----------------------------------------------------------------
+  Transforming "Code Set" to "codeSet"
+  Transforming "Code Name" to "codeName"
+  Transforming "Code Value" to "codeValue"
+  Returning empty string for header "description"
+  Returning empty string for header "extra_column1"
+  Returning empty string for header "extra_column2"
+  Returning empty string for header "codeSet"
+  Returning empty string for header "codeName"
+  Returning empty string for header "codeValue"
+  Returning empty string for header ""
+  Returning empty string for header "_1"
+  Returning empty string for header "_2"
+
+Parsed data (first row):
+{
+  "": "Extra Data 2"
+}
+
+Total rows parsed: 3
+
+
+SUMMARY
+=======
+
+Expected behavior:
+- Test Case 1: Headers should be renamed according to headerMap, unmapped headers kept as is
+- Test Case 2: Headers should be renamed according to headerMap, unmapped headers should be ignored/removed
+- Test Case 3: Headers in validHeaders array should be kept, others should be ignored/removed
+- Test Case 4: Workaround test - using empty string instead of null
+
+Actual behavior:
+- Test Case 1: Works as expected
+- Test Case 2: BUG - Causes TypeError when trying to process null headers
+- Test Case 3: Same issue - TypeError when returning null
+- Test Case 4: Check if empty string works as a workaround