Comment 8 for bug 1839185

Experiencing exact same problem. Originated for me when upgrading from lxml==4.3.5 to lxml==4.7.1.
BeatufiulSoup version remains unchanged. Since from x.y.z "y" was changed, it shouldn't break backward compatibility when actually it does (if we think that the BS is the root of the issue). Otherwise, sounds like an lxml issue.

Will try to dig deeper, anyway