He might mean the zone is flagged as a raid zone (aka no mercs), but I haven't done that one yet. Just a guess.
Sorry, wasn't clear it was late. When you get the group mission the dynamic zone you get as well was showing 54 instead of 6 for max players. Not sure if that's expected or not. It did not affect the mission and we finished correctly and received the lockout timer just seeing that 54 gave me pause.