Users started receiving limit exceeded error while trying to save a CASE from this afternoon and it appears to be sporadic (it gets saved after multiple attempts) but happening 80% of the times. In debug logs, it shows "EXCEPTION_THROWN||System.DmlException: Upsert failed. First exception on row 0; first error: LIMIT_EXCEEDED, limit exceeded: " but not sure what went wrong. I have made sure that there no SOQL limt exceptions in the logs and also, nothing was changed/deployed in past one week (neither configuration nor code changes). Any thoughts?