Despite hall if fame showing >$500M net worth for over a day, the Moneybags achievement seems to be stuck at 497M and doesn't trigger.

The bug seems to be an order of operations issue. It is calculating NW for achievements *before* it calculates the updated NW. You can tell this because the achievement NW listed is the prior days HoF NW value.

There was a bug with a database change that caused the reset not to happen that day. Diablo triggered it for the likes of refills etc but the stats/nw scripts don't get run until the following day so it should be correctly updated now.

Apologies for the late reply, just now catching up on bugs here now that they're all in one place.

I believe the issue was as Kwyy said but if it reoccurs please tell me.