Performance in Cordor Outskirts since last patch

[Party in the forest at midnight]

Since the last patch I've had an issue in the Cordor Northern Outskirts where the game gets really, really choppy the longer I'm in the zone. It usually starts happening after about 5 minutes of being there, and gets worse the longer I'm in the zone. The problem goes away as soon as I change to another zone. I don't think it's the specific tileset, spending time around Darrowdeep doesn't cause the issue to happen.

I've tried turning off the new effects the patch added, but those don't actually cause the problem. And I don't suffer the issue in any zones with a lot of water.

The only override I'm using is a skybox override. Nothing on my end has changed since the patch.

I'm trying to isolate exactly what it is that causes it, and I'm at a loss. Are there any options I could try turning off? Is it possible there's a script or placeable that interacts with the patch weirdly? I can try and find other zones where I have the same issue and see if there's any similarities.