Folder thumbnails suddenly get black backgrounds

[hologram1]

Over time when I browse, the folder thumbnails suddenly get black backgrounds. I don't have a color filter that would do this, and I don't use dark mode.
When I refresh the thumbnail cache I end up reverting more to have black backgrounds. Clearing the cache doesn't change them.

[admin]

I assume you have set the FolderThumbsShell=1 tweak?

If that's the case I can reproduce your issue (it was a side-effect of recent changes to thumbnail creation) and it will be fixed in the next beta.

[hologram1]

Yes I have that tweak set.

Thank you!