Bug: tmm displays wrong fanart

I am using tmm 4.1.6 (Windows 10) I have the problem that tmm is displaying the wrong fanart. Instead of displaying the fanart of the film it displays the one of the collection.

The correct file filmname-fanart.jpg does exist. Also the URL of the fanart is correct. In the same folder exist two additional fanarts

movieset-fanart.jpg
<movie set name>-fanart.jpg

If I remove the film from tmm and update the source then tmm shows the wrong fanart. If I move the file <movie set name>-fanart.jpg then tmm does not show any fanart. If I remove afterwards the film and update the source then tmm shows the correct fanart.

This happened after I renamed the film (outside of tmm). Not sure whether this is the reason for this behaviour. But in generally this shouldn't be a problem (since nfo, poster & fanart existed)