This problem seems to have been reported and fixed upstream:

https://github.com/quodlibet/quodlibet/commit/5f55431a28509fd4f4f7b40dc246f3d34fa8549e

Since no newer release has been out, I guess we can backport the commit itself.
I've tried with the attached patch. The operon tests still fail due to some
weird utime magic, a problem also known and discussed at:

https://github.com/quodlibet/quodlibet/pull/4053/commits/06a32b319f065550efe0d2a9ff10ca6bdc32b893

So I guess we could backport that as well. Does anyone have a better fix ?