Shazlewood If you are on free version, then yes - there is a limit of 12 persons. But there is no limit on how much faces there can be for one person.
It is possible that sometimes program may get confused with your input and become “shy” of proposing new faces for existing people. However, if you just go and manually confirm few new faces on the photos for the same people, wihtout waiting for automatic suggestions, this might give the program new “inspiration” and it might start suggesting again, based on on new information you provided to it.
