Tree Colliders Enabled causes First Person Character to fall through Terrain?

I have a rather large terrain with several trees and details. Everything worked fine while pressing play over the last few days but now I am encountering two problems which seem to be connected:

When Enable Tree Colliders is checked, my First Person Controller falls through the terrain.

When Enable Tree Colliders is unchecked, my First Person Controller is just fine and stays on the surface.

On a related note, I am unable to place anymore trees or details. I have not added anything nor have I altered anything. These two issues occurred at the same time and was easy to diagnose thanks to previous Answers here.

I’ve tried everything I can think of.

Hi there,

I have the same problem. Have you found any solution to this?

Thank you!