The solution you've submitted is not the root of the issue.

I've reproduced the issue on the test server:

• In http://test.musicbrainz.org/edit/14459753 I'm editing a medium, changing one track artist credit using an artist I've just created (http://test.musicbrainz.org/edit/14459752).
• The problem is that the "Edit medium" edit doesn't appear in the new artist editing history (http://test.musicbrainz.org/artist/e128a3dc-a3c9-4fa4-84b3-77d180f7ba44/edits), so Modbot checks in edit_artist and thinks it's OK to delete the artist.

Ah, I see. Should the edit medium appear in artist editing history?

The question is more general:

• either every edit (type) involving changing artist credit must appear in each involved artist editing history
• or the logic of Modbot cleaning artists should be changed (with a yet to be determined algorithm)

Never got started (that was a different issue)

Same problem with Cam Thơ in http://musicbrainz.org/edit/14490873

This doesn't appear to be fixed:

http://musicbrainz.org/edit/14555858
http://musicbrainz.org/edit/14555876

Those artists were added only for these artist credit edits; it's reported to me that they were removed because they were empty by modbot.

I can't find it since http://musicbrainz.org/user/VxJasonxV/edits?page=7 is 500'ing on me.

See above comment; I don't think this is fixed, unless it's a related issue that I couldn't find.

Those edits were entered on the 2nd, this wasn't fixed until the 8th.

This issue has apparently returned: See e.g.
http://musicbrainz.org/edit/17177177
where a newly added artist got deleted before the artist credit edit passed.

Return the status back to fixed - after further checking, the issue that has been seen more recently is actually edits failing due to artist merges, not due to modbot removing the artist.

Drop the incorrect 'affects version'