I distinctly remember a problem I had in this fight, which was something like, skills couldn't go past the doorstep (the back door in your screenshot). The door bugged out; it didn't disappear when it was destroyed. It just stayed there looking good as new, but I could go through it. However, skills couldn't go past it. I was on the outside right next to the door and cast Laser Ray into the room, but it was blocked at the doorstep. When Jonathan got to the doorstep, he and my Sebille were right in front of each other but on opposite sides of the door, and I couldn't attack him at all, and couldn't teleport past him either. Basically we could go through the door (because it was destroyed), but somehow skills and vision were both blocked at the doorstep.
-Enemies just runs to their destination, only to reappear back at their starting point where they now starts running for real
Now that you mention this, I *very vaguely* recall something like this, and I was like wtf when it happened, but then as the fight went on I forgot about it. Good thing is that I just had half my team walked inside and the other half stayed outside and I also never let anyone die, so nothing worse than these happened to me. The problem was just the blasted door; other than that, combat inside or outside the house was fine to me.
Long story short, I agree that there definitely is something fishy about this building.
EDIT: sorry about the dead dudes. Hope you still have a save before the fight happened so at least you could always go back to that.