OK, so it wasn't just a dogfood-specific problem. The new problem seems to be stuff like this:
2018-12-11 06:42:52 INFO Failure updating bug u'564437' on https://bugzilla.mozilla.org (local bug: 810622): https://bugzilla.mozilla.org: Fault 32000: API key authentication is required.
So I guess we need to work out what's changed about BMO's authentication arrangements.
OK, so it wasn't just a dogfood-specific problem. The new problem seems to be stuff like this:
2018-12-11 06:42:52 INFO Failure updating bug u'564437' on https:/ /bugzilla. mozilla. org (local bug: 810622): https:/ /bugzilla. mozilla. org: Fault 32000: API key authentication is required.
So I guess we need to work out what's changed about BMO's authentication arrangements.