Hey, so run petra's run as normal, but, when you get to running the heart before starting the encounter have everyone except the fire team lead kick to orbit then join back up, switch fire team lead then have that person do the same. It clears the cache or something but allows you to complete petra's run without getting guitared. That's how my group did it.
The bad code is produced off of tracker emblems. Everyone has to wear an emblem that just says Level 50, and you shouldn't get it. I don't know why, but this definitely works. Just did it last night.