Error when trying to update events that were created for a contract invoice

Summary:

Error when trying to update events that were created for a contract invoice

Content (required):

Two events were created for a contract invoice (the invoice is now in Draft status), see screenshot.

As we try to click on the event number to update it, an error pops up: "Another person is using the record you're attempting to update. Try again later".

I thought it came from a blcoked session, but even after closing all sessions, log out/back in Oracle, this did not solve the issue. Also, excluded the idea of

browser cache, as issue is the same on multiple browsers, and even for multiple users (I tried it myself and getting same error).