We were doing mass deletes of item fulfillment records that come in from an eCommerce Site that requires 2 day delivery, but they send us 3 day labels. (subtle, I know).
The mass update script deleted the tagged item fulfillments.
We wrote a scheduled script (that I'll have to manually trigger) to run off a new saved search. Had a bunch of trouble getting it to even kick off.
That was the weird part-the mass update wouldn't even start. At all. Didn't fail; just didn't go. Stumped them at their end too. Hence the escalation. Critical because losing that Optimus <cough> badge is really important to keep sales up.