Date extraction regression: 2025-05-01-preview vs 2025-11-01 (GA) in Azure Content Understanding

If the same samples worked before and now fail consistently, I would treat this as either a model behavior change or a service regression and open a support case with the project, model deployment, region, request time, and a few minimal sample documents.

As a workaround, I would make the output schema more defensive. Ask for the raw date string exactly as seen on the invoice, then normalize it in your own code with the expected locale and date format rules. Invoice dates are a place where relying on the model to infer the final normalized date can be risky, especially when day and month order may be ambiguous.