[Bug] Why are this trees floating with the wind?

Hello!

I've run to a fun(?) but really annoying bug in my game. I have some tree prefabs in my scene with a wind zone, and when I bake the lights, some of then start floating. This doesn't make sense at all! If I delete them and put them on the scene again, it's fixed, but as soon as I bake the lights again, I get this error. Maybe it's the prefab configuration? I've downloaded it from the unity assets (Coconut Palm Tree Pack).

Any idea on what is causing this? Thank you!