Hi,
Looking at the code in the latest version, the Async Tick (alongside other tick functions) should be unregistered when the actor is either destroyed or when a level is streamed out (in which case components are unregistered incrementally). See ULevel::IncrementalUnregisterComponents.
If RegisterAllActorTickFunctions is not being called as part of that, then something is not working as expected.
Can you share the call stack of the crash? I can check with the team to see if this is a known issue or if it is already fixed.
If the Actor or Component ptr is not null, but points to invalid memory. It means the actor was garbage collected without being removed from the async callback list. So yes, in that case the check you saw will likely not help to catch that issue.