Testbed - Issue with LLAMA models

[gotsysdba]

This is a consolidation issue based on a number of related issues raised against the same problem:

• Llama3.1 issue using in evaluation #214
• Testbed: Q&A generation #213
• Exception in TestBed - Q&A Generation #126
• Testbed - Index out of Range #107

Review above (now) closed issues for more information specific to the errors and investigations. Resolve under this issue.