Anyone else found this "bug" in Apple Music on their Mac?

Has anyone else found that their Album Artwork has acquired an annoying little visitor (se the attached image)? I know for sure that the artwork images that came with my downloads were originally "fly-free", but every so often one or two appear. It's definitely part of the image, so I can only image that it's either been downloaded on the odd occasion when I haven't had the "Automatically Update Artwork" box unchecked., or there's a pretty clever virus out there that is actually over-writing the image file.

This seems to be a random occurrence, never more than a couple show up, and not the same album as far as I can tell (I have over 1000 albums so easy to miss one without checking every image. I've cleared out the affected images and replaced them with "clean" versions, and I've made sure the "Automatically Update Artwork" box is unchecked, so I'll have to wait and see if any more appear