There were a whole bunch of meta questions asked in Super User over the past few days.
However none of these were delivered to my inbox.
What's up with that?
I think I've found the issue here, has to do with how we generate, queue and send inbox items overall. It comes down to we were using one inbox item object and in a tight loop sending that to all moderators who a) aren't employees, b) aren't devs and c) didn't post the question.
The issue is that we send almost everything to redis via it's own background fire and forget task to maximize throughput between a particular web server and redis. Unfortunately that means that there are some extra considerations when re-using objects. In this case, we set the AccountId to determine which inbox that item goes to in that loop, and since that's not synchronous, there was a chance of some mods getting dupe messages and some getting none.
This possibility has been corrected, but I can't confirm (easily) that it is the exact cause due to how we'd have to reproduce this race. Please comment if you still see this issue after the next build tonight, as we obviously need to dig deeper for other reasons this is happening.