I'm currently working on the rowiki labels campaign and I've encountered a number of revision not found errors:
{ "code": "revision not found", "message": "Nu s-au putut obține metadatele pentru revizia 10501894" }
These should be identified and skipped automatically or manually (e.g. the user clicks a "Skip" button), as currently any kind of response seems inappropriate.
See also T161104 for a similar issue with hidden revisions.