This is a great, but it does not save the renamed titles. on page reload, we are back to default naming.
Same issue on my end. I ruled out plugin and theme conflicts, cleared my browser cache, no dice.
I had a similar issue that I was able to solve, I’m not sure if this will help your situation. I was using the clone field to clone another flexible content field. In the clone settings I was using Display -> Seamless which would cause it to break this functionality disable/rename. If I switched to Display -> Group it resolved the issue.