Another user has updated this resource since this page was loaded. Please refresh the page and try again.

Sounds like somehow you and someone else has a record being edited at the same time.

Check code and make sure correct records are being loaded.

@jlrdw I changed manually a field default value at the database and since then this message appears.

Should I delete all migrations and create them again?

That's a good question as I don't know what was changed. I would use DD and the network tab to see what is happening. Definitely sounds like some default value then is not correct.