Hullbreaker Sasquatch Attacking Party Members Outside Boss Room Bug (Not Knock-back)

Date: March 5th, 2015
Time: Around 9:30 PM PST
Duty: Hullbreaker Isle
Boss: Sasquatch
Area: Bridge just before the first boss room.

Events leading up to encounter with the bug:
Pulled first set of mobs immediately up the path after buffs, incidentally got aggro on the the patrolling Harpeia mob, hugged the right-most wall to skip the preying mantis mobs, grabbed the following monkey and the wasp. Afterward, pulled every mob to the last two monkeys on the bridge in which case Sasquatch, instead of doing the knock-back move on the bridge when you get too close, charged the party and started attacking party members. Sasquatch appeared on the enemy list but was untargetable and did not get effected by AOE enmity-generating moves such as Flash, at least to the best of my knowledge as it was somewhat hectic. Seems like the game treated the encounter as a boss battle due to the fact we gained access to two limit-break bars.

Here's also video evidence I recorded via my PS4:

Youtube: https://www.youtube.com/watch?v=IxtjFSiQft4

Recorded after the initial charge but still clearly shows that Sasquatch was attacking our party members outside of the boss room with auto-attacks and AOEs.

I've only seen this when I take all the monkeys on the bridge, but I have seen the same thing.

Mpk'd my friend when he came healer by exploiting it, was hilarious to the 3 of us lol