Noting that after several times of me shrugging my shoulders at people showing me data with errors that shouldn’t have been able to be saved, I was able to replicate the ability to save an event with an error through brute force of attempts. Ticket and video linked above.
The unknown that I’m trying to gather more info on is on if the ability to save is random, or if it specifically requires the repetitive nature of the attempt. I’m fairly confident it requires a lot of attempts/specific effort to go around the program rules to make it work.