Enmity upon start of Coil Turn 5 Since 2.1 appears erratic

Since the 2.1 patch, our raid group has found that the enmity upon starting the fight with Twintania is unusual.

We are currently having our off-tank proxy-aggro the mobs while the main-tank Shield Lobs Twintania. Then, before any other threat-generation actions take place, the additional enemies are Flashed and the fight begins in earnest.

However, we are finding that the additional enemies will all attack a random party members instead of proxy-aggroing the off-tank as normal. This random party member is often a healer, but sometimes a seemingly-random DPS. This occurs despite these players being idle outside of the arena with no HoT spells and with pets on Steady.

We confirmed that this behavior does not occur if the party stays at the top of the zone near the entrance after buffing has already taken place; therefore, the enmity does not appear to be due to pre-fight buffing. However, we are not sure what is causing the behavior.

This mob behavior is not a huge deal -- the off-tank merely recovers the wayward additional enemies, and we proceed as normal -- but it is somewhat annoying. I thought I would try asking here to see if anyone has encountered the same thing and whether they have diagnosed the cause of the behavior.

Though I don't know the cause, this happens to me quite often. Thankfully being drg I just life surge dfd right after the eventual hit. I would like to know the battle logic as to why. Previous threads have suggested job and gender as the most common denominator. I personally think it is the way the floor paneling is designed but have not had the opportunity to test in low enough Rez to see where they intersect. There was a similar issue in ffxi where if you stood on an intersection the chase logic would break and mobs would never find the propped path to get to you.

It's been happening since before the patch. Last night the mobs came to me (BRD), but once they reached me, they did not attack and instead went to the proper MT/OT. I think it's due to something random like last person to enter the battlefield / exit the CS as it has happened to DPS and healers randomly.

I noticed it during out Twintania attempts this week as well. Doing nothing differently I almost always lost adds upon pull. At first I thought it was the BRD using Foe Req but now it seems it's a bug maybe?