Mine was not really solved - more like, "diagnosed": if the polling time was set in the future at some point (e.g. time sync was misconfigured, or just system time set improperly), advanced alerts will not fire until that future occurs. E.g. it's midnight but server was set to 2am and then reset back to midnight, there will be no advanced alerts till 2am. Does that make sense?
It's not easy to discover as I don't believe anything in UI or on Orion Web Console indicates there's a problem.
In your case: do you have any advanced alerts that work?