Could it be that the clothed character was either taunting, guarding a girl that could get equipped, or a girl that could get equipped was stealthed?
If so, I think I know what causes this. Taunt, guard, and stealth change the targetting, after the move is selected. So Equip thinks it can equip something, but gets rerouted to another target where it can't equip anything and then breaks.
Edit: I did some further testing and that's seems to be it. It doesn't show in my dev build, but in the Export build it also gives the "false" and crashes the game. No need to send the save or logs anymore.