The issue seems to stem from the wind shader not working with the lightmapper. You basically have two options. One is to turn off lightmaps on the prop by setting the Bake Lighting property to Off. The other is to use a material without wind. Most trees have a second skin setting called something like no_motion, which disables the wind effect.

Thats very interesting, I was wondering if it was wind related. I was unaware the lightmapper had something to do with it though. Could my lightmaps in the map be messing up? Would deleting them and re-adding them work? I ask this because I'm also having issues with the daylight bleeding into otherwise dark hallway corners and giving overall poor quality for the lighting indoors. Block light walls don't seem to seal everything in completely either.

I think it's an issue with how the engine compiles lightmapped staic props into the map, rather than anything on your end. The engine makes a copy of each lightmapped prop to give them unique UVs on the lightmap atlas, and then saves them in to the map file. This seems to change the model origin, which might be the reason the wind shader breaks.

Regarding preventing light leaking through, make sure you have good topology on your world geometry. Check that the faces don't extend beyond the corners into the walls.

Originally posted by GammaGoose:

Anyone else have this issue? The trees I've placed in a map of mine seem to move up and down in a bobbing motion. They are set as static props, Even removing them and placing them back in they seem to do the same thing. Sometimes at varied speeds and height. I'm not sure how to fix them.

https://youtu.be/0-jD4MkmMv0?t=50

Greatly appreciate the feedback my dudes, thanks!