I think I triggered some unintended results at the orc beach battle prior to first entering Cyseal.
Having played this many times, I knew the fight was coming and ran my melee character down to the same point I always run him (towards a corpse near the water's edge). Usually that places me into fight mode as the orc ship arrives, the orcs (and a human) debark, and rush into their positions on the beach and the turn-taking begins. This includes the NPC guards who are already fighting another large orc who is already on the beach.
Instead, what seems to be happening now is this: I run down to my spot, the orc ship arrives, and before the invading force has even gotten both feet on the sand the battle goes into turn-mode. In other words, the orcs are all clumped up by the boat. The consequence of this is that this battle is now far enough away from the NPC guards (who are fighting a different large orc) that they're never included in the fight. I end up having to kill the human cultist, orc shaman, and his two orc guards with my two character party (while the guards just pace around on the beach in real-time after slaying the orc we spotted them fighting from further up the cliff).
This seems to be repeatable now, so it's not a fluke. I can get the battle to play out "normally" by initially running my character towards the guards instead, but otherwise it seems to break down pretty reliably.
Here's a screenshot of what I'm talking about:
Note the guards standing around at the top right of the screen, not engaged in the battle. You can see they're not even present in the portraits up top. You can also see over on the left how the orcs have barely departed the boat and not had an opportunity to complete their run onto the beach.