Submit button not actually submitting, but no error message

Summary:

Since the 26.07 update was applied last weekend, the client is seeing very strange behavior in one dimension in EDM, where Requests become stuck, unable to be submitted but with no system error or validation failure messages to explain why, and unable to be reassigned to another user. The behavior exists in both Test and Prod instances, but so far is only present in this dimension, and not others, in the same Application.

Content (please ensure you mask any confidential information):

In the Natural Account dimension, Master (Universal) Application in EDM:

1. When loading an Excel file into a Request, EDM's message pop-up says it's loaded all records successfully, but when the pop-up is dismissed, the active Request shows zero lines: