I hope you're doing well. I wanted to jump in and share that I'm facing a similar challenge with shared users in an app I've developed. My client also shared the app with their team, but the shared users are unable to submit the form as expected.
I've double-checked that the users have the necessary editsucces permissions for all the relevant lists and sites, yet they still can't save the data. It's been a bit of a puzzle, and I've been exploring possible solutions without much luck so far.
Has anyone else come across this issue or found an effective workaround? Any advice or suggestions would be greatly appreciated to help address this problem.