Picard crashes donwloading coverart. The crash can be during the initial download, or after choosing a different album version. The crashlog:

Traceback (most recent call last):
  File "/home/xxx/tmp/gitlocal/picard/picard/ui/coverartbox/coverartthumbnail.py", line 187, in set_data
    pixmap = self._pixmap_cache[key]
             ~~~~~~~~~~~~~~~~~~^^^^^
  File "/home/xxx/tmp/gitlocal/picard/picard/util/lrucache.py", line 67, in _getitem_
    value = self._dict[key]
            ~~~~~~~~~~^^^^^
KeyError: -4319694363775932833

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/home/xxx/tmp/gitlocal/picard/picard/ui/coverartbox/_init_.py", line 206, in update_metadata
    self.cover_art.set_metadata(metadata)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^
  File "/home/xxx/tmp/gitlocal/picard/picard/ui/coverartbox/coverartthumbnail.py", line 323, in set_metadata
    self.set_data(data, has_common_images=has_common_images)
    ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/xxx/tmp/gitlocal/picard/picard/ui/coverartbox/coverartthumbnail.py", line 192, in set_data
    if pixmap.loadFromData(self.data[0].data):
                           ^^^^^^^^^^^^^^^^^
  File "/home/xxx/tmp/gitlocal/picard/picard/coverart/image.py", line 466, in data
    return self.datahash.data
           ^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'data'