The implementation of the log filters containing this bug appears brittle, and seems to have a high risk of depending on undefined (non-explicitly-supported) behavior. As such, it's worth evaluating whether they're providing enough value to be worth maintaining in this library. One reasonable "fix" could be to simply delete the log filters and let downstreams deal with filtering favicon and static content requests in their own log configurations if they care.
Originally posted by @zachmullen in https://github.com/girder/django-composed-configuration/issues/121#issuecomment-815339781