diff --git a/.github/workflows/qa.yml b/.github/workflows/qa.yml
new file mode 100644
index 0000000..5bb6db7
--- /dev/null
+++ b/.github/workflows/qa.yml
@@ -0,0 +1,40 @@
+---
+
+name: Quality Assurance
+
+on:
+    pull_request:
+    push:
+        branches: master
+
+jobs:
+
+    parse-xml:
+        runs-on: ubuntu-latest
+
+        steps:
+            - uses: actions/checkout@v4
+            - uses: actions/setup-python@v5
+            - run: pip install lxml
+            - uses: jannekem/run-python-script-action@v1
+              with:
+                  script: |
+                      from pathlib import Path
+                      from lxml.etree import parse, XMLSyntaxError
+
+                      encountered_errors = []
+                      root_path = Path.cwd()
+
+                      for file in root_path.rglob("*.xml"):
+                          try:
+                              parse(str(file))
+                          except XMLSyntaxError as e:
+                              encountered_errors.append(f"{file.relative_to(root_path)}: {e.msg}")
+
+                      if encountered_errors:
+                          print("\nInvalid XML encodings were found:")
+                          print("---------------------------------")
+                          print("\n".join(encountered_errors) + "\n")
+                          raise SystemExit(1)
+
+...
\ No newline at end of file
diff --git a/xml/transcript/gm_duesseldorf/KK123_20/01.xml b/xml/transcript/gm_duesseldorf/KK123_20/01.xml
index a148a0a..c3ef677 100644
--- a/xml/transcript/gm_duesseldorf/KK123_20/01.xml
+++ b/xml/transcript/gm_duesseldorf/KK123_20/01.xml
@@ -473,7 +473,7 @@
                     <seg f:left="#ne2">⏓</seg>
                 </line>
                 <line f:pos="between" xml:id="Aengstlich"><handShift new="#ri_bl_lat"/><orig>Ae</orig>ngſtl<anchor xml:id="lich4"/>ich drückend<anchor xml:id="de"/>e Schaale</line>
-                <line f:pos="over" xml:id="lm"><handShift new="#ri_t_lat"/><orig>Ae</orig>ngſtl<anchor xml:id="lich5"/>ich dr<anchor xml:id="druek"/>ück<anchor xml:id="ken"/>end<anchor xml:id="de2"/>e Sch<anchor xml:id="Schaa"/>aal<anchor xml:id="le"/>e</line>
+                <line f:pos="over" xml:id="lm"><handShift new="#ri_t_lat"/><orig>Ae</orig>ngſtl<anchor xml:id="lich5"/>ich dr<anchor xml:id="druek"/>ück<anchor xml:id="ken"/>end<anchor xml:id="de2"/>e Sch<anchor xml:id="Schaa"/>aal<anchor xml:id="le2"/>e</line>
                 <line f:pos="between" xml:id="lcb" type="inter"><handShift new="#ri_bl_lat"/>⎼
                         <seg f:left="#lich4">⏑</seg>
                     <seg f:left="#de">⏑</seg>
@@ -539,8 +539,8 @@
                     <seg f:left="#tend2">⏑</seg>
                     <seg f:left="#schluepft2">⎼</seg>
                 </line>
-                <line f:pos="between" xml:id="Sonnedurchstrahleten"><handShift new="#ri_bl_lat"/>Sonn<anchor xml:id="ne3"/>ed<anchor xml:id="durch"/>urchſtr<anchor xml:id="strah"/>ahl<anchor xml:id="le2"/>et<anchor xml:id="ten"/>en <anchor xml:id="Ae"/>Aeth<anchor xml:id="ther"/>er</line>
-                <line f:pos="over" xml:id="lr"><handShift new="#ri_t_lat"/>S<anchor xml:id="Son"/>onn<anchor xml:id="ne4"/>ed<anchor xml:id="durch2"/>urchſtr<anchor xml:id="strah2"/>ahl<anchor xml:id="le3"/>et<anchor xml:id="ten2"/>en
+                <line f:pos="between" xml:id="Sonnedurchstrahleten"><handShift new="#ri_bl_lat"/>Sonn<anchor xml:id="ne3"/>ed<anchor xml:id="durch"/>urchſtr<anchor xml:id="strah"/>ahl<anchor xml:id="le3"/>et<anchor xml:id="ten"/>en <anchor xml:id="Ae"/>Aeth<anchor xml:id="ther"/>er</line>
+                <line f:pos="over" xml:id="lr"><handShift new="#ri_t_lat"/>S<anchor xml:id="Son"/>onn<anchor xml:id="ne4"/>ed<anchor xml:id="durch2"/>urchſtr<anchor xml:id="strah2"/>ahl<anchor xml:id="le4"/>et<anchor xml:id="ten2"/>en
                         <anchor xml:id="Ae2"/>Aeth<anchor xml:id="ther2"/>er</line>
                 <line f:left="#ne3" f:pos="between" xml:id="lcl" type="inter"><handShift new="#ri_bl_lat"/>⏑ <seg f:left="#durch">⏑</seg>
                     <seg f:left="#strah">⎼</seg>
diff --git a/xml/transcript/gsa/389773/0002.xml b/xml/transcript/gsa/389773/0002.xml
index 3c1e520..a5a6453 100644
--- a/xml/transcript/gsa/389773/0002.xml
+++ b/xml/transcript/gsa/389773/0002.xml
@@ -361,7 +361,7 @@
                 <anchor xml:id="used"/>
             </zone>
             <zone f:top="#lSie" xml:id="lb">
-                <line f:right="#Sie" xml:id="lb"><handShift new="#g_t"/>Sie</line>
+                <line f:right="#Sie" xml:id="lb2"><handShift new="#g_t"/>Sie</line>
             </zone>
             <zone f:right-left="#mainzone">
                 <line f:bottom="#Es" xml:id="laf"><handShift new="#g_t"/>Nun</line>