Hey Player,
So when painting your foliage meshes, be sure to have the ‘Collision with World’ enabled which will check to make sure it is colliding with the surface it is being applied.
Collision with World
Be sure to rebuild your geometry after having checked this option on pre-painted foliage. If that is still not working, you can select the re-apply tool, scroll down to the ‘Collision with World’ option, select the correct foliage type, and then repaint the foliage. It will then re-locate your meshes to the geometry’s surface of your landscape.
In regards to the scuplting tool not functioning after a certain time, are you able to reproduce this in a blank project, or have steps to get to this point?
Let me know if you have further questions or need additional assistance.
Thanks,