Not having participated in the Test Realm for Marleybone and Aquila, I was unaware of these until they happened to me.
#1. Bishop's AI is faulty. He appears to be attempting to cast Leech every round in which he is hit by a non-magical attack, whether or not anything to leech remains on the battlefield. This makes him ludicrously easy for a Buccaneer or Swashbuckler to defeat, once his companions are taken down, as he makes no effort to attack or move if you hit him each round.
#2. An old bug has resurfaced. Namely, the bug which places you standing in the sky outside of an island when trying to pass through a door on the island. This happened to me on the Isle of Dogs, at the gate between the docks and the island proper. Porting to the life fountain fixed it, as before.
#3. Another old bug resurfaced on the Isle of Fetch, when fleeing from battle resulted in my seeing Sgt. Benton running past me and off of the pier, fading away into the distance.
#4. Weapons from chests in Beachhead are borked. In a run through the entire thing, all three spokes, the battery, etc., precisely one weapon (a Cherubim Set) dropped which was above level 20, if I am not mistaken. All other weapons appeared to be levels 10-15, primarily halberds. Most armor that dropped was of a level commensurate with Marleybone.