In those cases, shouldn't the image work if the user were to try again later, though? The only thing I'm still wondering is why it's so consistent for some users, while others never have the problem.
Perhaps certain of their CDN servers are acting up while others are fine, or certain CDN servers are a lot busier than others, in which case I suppose it could be a regional thing.
Hopefully they get the issue resolved soon so we can be sure that it fixes this issue users are having with the Discogs Tagger as well.
Thanks for sticking with it Let, your efforts working on this plugin are very much appreciated.