Problem with duplication of blocks

Since some times I’ve more and more problems when duplicating a block!

in fact I receive this message:

I don’t understand why! I’m just duplicating a normal block!

The problem is that if I ignore the above message then the app don’t function anymore the way it should.

Hence, what should I do? Try to modify my code in the actual App or start from scratch a new App which is quite ennuying…

Someone could help ?

I’m following this thread as i experienced a couple of times the same issue