I experienced a problem with certain ally NPCs not engaging during fights in solo Story missions.
I noticed this occurs most often for me during the current Living Story episodes (mostly in Bloodstone Fens), though I have seen it before in other story missions, however the specifics escape me. In particular, Rytlock and Marjory will often refuse to to engage enemies or heal a downed player, usually remaining completely immobile, resulting in quite a lot of frustration, swearing, and resets. Marjory will sometimes break out of this stall and heal the player, but then stall again. Rytlock seems to get and stay stalled. Canach seems to be unaffected, always engaging and/or helping the player.
I tried several methods of un-stalling them, such as moving close to or on top of the stalled NPC, clicking on them, dragging enemies to them, dying and restarting at the checkpoint, however the only way that worked was to restart the current mission from the beginning. Even then, though, it’s not guaranteed that they won’t stall again.
I attempted to duplicate the conditions of the stall several times, resulting in at least two actions that I believe lead to it. The first being that the player runs too far ahead and skips enemies, in which case Rytlock and Marjory will run up next to the enemies and stall, neither attacking nor gaining aggro. I noticed that this behavior is sort of similar to when a player runs too far ahead and the NPCs stop and wait for the player to get back in range before continuing on. No idea if that’s related, but I understand those conditions are so that the player doesn’t miss out on any dialogue.
The second condition was engaging in a fight too quickly after dialogue, both with and without Rytlock or Marjory being the ones engaged in dialogue. In this instance, Rytlock is completely stuck and Marjory will help heal about half the time before stalling until healing is needed again.
I’m not sure if this has happened to anyone else, as searching the forum didn’t lead to any similar sounding incidents.