Boss fight - Staying inside the arena while not in the fight

This occurred during a "natural" boss fight, not one spawned with an egg (that detail may or may not be important) I didn't see this for "myself" making the report on behalf of DrFishy44 From what I was told, they were standing in the boss arena, were told to freeze to join, and moved, "kicking" them from the fight, however, they were not teleported out of the arena. They stayed in the arena, but weren't considered to be part of the fight. Usually if you are in the arena when a fight starts, and you don't join it, I'm pretty sure you get teleported out of the arena (could be wrong on this) I may test this with my alt later (if I manage to replicate it, might delete this report/make a more detailed one)