before being corrected, Q2105758 was having an invalid claim (no datatype, invalid claim id). A possible reason: the item was merged and the merged was reverted 3 years later, so any cleanup on items using the delete property would have missed it...
In the GUI, the issue is marked with big red warnings, but from the API or dumps, this bizarre data may end up crashing tools that expect a consistent claim format: could there be a way to garbage collect this kind of edge cases? It doesn't appear in SPARQL request (un?)fortunately
[Edit]: that said, as I'm currently parsing a full dump, I should be able to spot any other error of this kind
[Edit 2]: after parsing the whole dump, there seem to be no other case