Sometimes - but not always - I get this debug log output:

E: 14:52:17,175 util.thread.run:51: Traceback (most recent call last):
{{ File "picard\util\thread.py", line 47, in run}}
{{ File "picard\file.py", line 117, in _load_check}}
{{ File "picard\formats\id3.py", line 192, in _load}}
{{ File "picard\formats\id3.py", line 572, in _get_file}}
{{ File "site-packages\mutagen_file.py", line 49, in _init_}}
{{ File "site-packages\mutagen_util.py", line 140, in wrapper}}
{{ File "site-packages\mutagen\id3_file.py", line 394, in load}}
{{ File "picard\formats\mutagenext\compatid3.py", line 64, in _init_}}
{{ File "site-packages\mutagen\id3_file.py", line 77, in _init_}}
{{ File "site-packages\mutagen\id3_tags.py", line 177, in _init_}}
{{ File "site-packages\mutagen_util.py", line 533, in _init_}}
{{ File "site-packages\mutagen_tags.py", line 111, in _init_}}
{{ File "site-packages\mutagen_util.py", line 169, in wrapper}}
{{ File "site-packages\mutagen_util.py", line 140, in wrapper}}
{{ File "site-packages\mutagen\id3_file.py", line 165, in load}}
{{ File "site-packages\mutagen\id3_tags.py", line 181, in _read}}
{{ File "site-packages\mutagen\id3_tags.py", line 596, in read_frames}}
{{ File "site-packages\mutagen\id3_frames.py", line 291, in _fromData}}
{{ File "site-packages\mutagen\id3_frames.py", line 179, in _readData}}
{{ File "site-packages\mutagen\id3_specs.py", line 510, in read}}
{{ File "site-packages\mutagen\id3_specs.py", line 475, in read}}
{{ File "site-packages\mutagen_util.py", line 995, in decode_terminated}}
LookupError: unknown encoding: utf16

If I drag & drop the same file from the same source directory to the same place at the left side of Picards unclustered files AGAIN, the error is gone and I can't reproduce it...