SureAI

As the topic.

This problem is known. I think everyone who played Enderal was quite irritated by it. Buuut... they cannot fix it (there was a post about it once). Apparently the gras isn't even there anymore in the editor. They have no clue how to remove it.

The floating grass bug is reported at least twice a day
Perhaps they should make a sticky post about it in the bugtracker.
And in fact it can be seen in the CK too, but whatever you try, it cannot be removed. It is ghost grass.