General Mayhem is the only boss battle I know of that is that glitchy! I rarely glitch on easy, but Ive never had hard work. Normal worked once.
Easy should work fine no matter what crew size you have.
Apparently Normal works if you have over three crew members, but Hard glitches when you have over three if I remember correctly...
Otherwise the only other glitch which happens is that sometimes the general bumps you into neverspace, and you need to type /stuck into your chat in order to get unstuck.