Error when loading the album Idomeneo with ID 
https://musicbrainz.org/release/838e15bc-8b5a-42e6-8848-107e8e3edd5b

In Picard, the album is indicates with a red disc flag.

this shows up in the album info dialog:

Traceback (most recent call last):
  File "album.py", line 453, in _finalize_loading_track
  File "metadata.py", line 627, in run_track_metadata_processors
  File "plugin.py", line 248, in run
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 216, in process_track
    work = parse_work(rel['work'])
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 173, in parse_work
    work.part_number = rel['ordering-key']
KeyError: 'ordering-key'
Traceback (most recent call last):
  File "album.py", line 453, in _finalize_loading_track
  File "metadata.py", line 627, in run_track_metadata_processors
  File "plugin.py", line 248, in run
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 216, in process_track
    work = parse_work(rel['work'])
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 173, in parse_work
    work.part_number = rel['ordering-key']
KeyError: 'ordering-key'
Traceback (most recent call last):
  File "album.py", line 453, in _finalize_loading_track
  File "metadata.py", line 627, in run_track_metadata_processors
  File "plugin.py", line 248, in run
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 216, in process_track
    work = parse_work(rel['work'])
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 173, in parse_work
    work.part_number = rel['ordering-key']
KeyError: 'ordering-key'
Traceback (most recent call last):
  File "album.py", line 453, in _finalize_loading_track
  File "metadata.py", line 627, in run_track_metadata_processors
  File "plugin.py", line 248, in run
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 216, in process_track
    work = parse_work(rel['work'])
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 173, in parse_work
    work.part_number = rel['ordering-key']
KeyError: 'ordering-key'
Traceback (most recent call last):
  File "album.py", line 453, in _finalize_loading_track
  File "metadata.py", line 627, in run_track_metadata_processors
  File "plugin.py", line 248, in run
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 216, in process_track
    work = parse_work(rel['work'])
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 173, in parse_work
    work.part_number = rel['ordering-key']
KeyError: 'ordering-key'
Traceback (most recent call last):
  File "album.py", line 453, in _finalize_loading_track
  File "metadata.py", line 627, in run_track_metadata_processors
  File "plugin.py", line 248, in run
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 216, in process_track
    work = parse_work(rel['work'])
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 173, in parse_work
    work.part_number = rel['ordering-key']
KeyError: 'ordering-key'
Traceback (most recent call last):
  File "album.py", line 453, in _finalize_loading_track
  File "metadata.py", line 627, in run_track_metadata_processors
  File "plugin.py", line 248, in run
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 216, in process_track
    work = parse_work(rel['work'])
  File "/Users/amaier/Library/Preferences/MusicBrainz/Picard/plugins/workandmovement.zip/workandmovement/_init_.py", line 173, in parse_work
    work.part_number = rel['ordering-key']
KeyError: 'ordering-key'