Getting Error : "Do not use the same path multiple times"

Hi Team,
Getting below error while adding 50th field in documenttype where 49 fields already exist and after click on “Done” below error is coming.
But after refreshing the page then able to see 50th field in documenttype.
I am not getting any error in logs, not sure whether it’s related to limit of fields or something different.
Need your help.

Could you post the error?

I’m guessing this is a UI error and not an error on the backend.