We have seen a few intermittent failures of RepeatingGenerator. The most recent is on test.wikidata:
https://travis-ci.org/wikimedia/pywikibot-core/jobs/35913559
IIRC, the previous ones have also been test.wikidata
My guess is there is insufficient recent change data on this wiki, and a looping problem is causing infinite looping.
Version: core-(2.0)
Severity: normal