Picard fails saving ID3 tags with iTunNORM tag

Picard fails to save ID3 tags that contain an iTunNORM comment, see https://community.metabrainz.org/t/cant-convert-bytes-object-to-str-implicitly/396592

E: 07:04:58,658 /home/phw/devel/musicbrainz/picard/picard/util/thread.run:56: Traceback (most recent call last):
File "/home/phw/devel/musicbrainz/picard/picard/util/thread.py", line 52, in run
result = self.func()
File "/home/phw/devel/musicbrainz/picard/picard/file.py", line 216, in _save_and_rename
self._save(old_filename, metadata)
File "/home/phw/devel/musicbrainz/picard/picard/formats/id3.py", line 363, in _save
tags.add(id3.COMM(encoding=0, desc=desc, lang='eng', text=[v + b'\x00' for v in values]))
File "/home/phw/devel/musicbrainz/picard/picard/formats/id3.py", line 363, in <listcomp>
tags.add(id3.COMM(encoding=0, desc=desc, lang='eng', text=[v + b'\x00' for v in values]))
TypeError: can only concatenate str (not "bytes") to str