As a mastermind, is there a maximum of cops possible to convert

JOKER

You can convert a non-special enemy to fight on your side. The enemy
must have surrendered in order for you to convert it.

Thanks to this wonderful skill, you can turn other cops. But last time I played, after I turned one of the cops, I couldn't turn another one. The cop surrendered but after that, while trying to turn him, I received a "Your persuasion capacities have been resisted" message…