Looks like some script tried to import genre pictures instead of genre descriptions.
Can you edit your genre list / does it show those values too? You should clean it up. Tools > Edit Lists > Genre
Which script did you use for retrieving information for the movies affected? It may need some correction.
If there are not too much movies under those "weird genres" you could simply alter the genre information by hand (edit multiple might help). Afterwards tree view should be back to normal.
What you have to do is clear BOTH Genre AND Subgenre and do a reupdate. You will have to edit each movie on each own. Multiple Edit will not work as it doesn't show genre for some reason. It shows blank, while it isn't. After that just refresh the Tree and everything will be back to normal.