Category Thumbnail not changed

Changed the thumbnail for some categories which worked fine. But for following category the thumbnail isn’t changed:

Renamed it from “Eingangstür” to “Eingangsbereich” in order to ensure that the umlaut isn’t a problem. Detected that the component “Türspion” doesn’t change the thumbnail.

Deleted the model “Türspion” and shared it as model, not as component which fixed the issue for the model’s thumbnail.

The thumbnail issue for the category remains!