This one may be a bit of a long shot, but I had a user having issues this morning when they went to edit a Survey123 submission (opened via a URL from Power BI) that one of the 5 repeats did not load into their form to be able to edit.
When I tried with my test account (same permissions as the user) I had no issues with the repeats. I made extra sure it was the same record and everything. I noticed that the record that is not appearing for this user has a different EditDate than the other 4 which makes me think it got disconnected somehow, though the ParentGlobalID is the same.
I came across some posts talking about the limitation of the maxRecordCount when loading the Inbox such as here, does this still impact things when you have a query to only load some of the records to the Inbox? Would this at all have any impact on some users differently than others?