Hi @Cory Cromer,
Thank you for reaching out to Microsoft Q&A forum!
The Azure Document Intelligence prebuilt US Bank Check model is specifically designed to process the front side of checks, extracting key information and other relevant details. Unfortunately, it does not support analyzing the back of the check for endorsements or signatures.
If your goal is to verify or detect endorsements, I recommend focusing on the front side of the check for training. You can train the model to extract relevant data from the front, such as any stamps or signature-like marks that might appear there. However, detecting endorsements or signatures on the back of the check is not currently supported by either prebuilt or custom models in Azure Document Intelligence.
I hope you understand. Thank you.