User reported game thread and async loading thread accessing a UGameplayEffect property at the same time:
The two threads are accessing the same memory, which we should have a mechanism to prevent. One thing to investigate whether that should be specific to the GameplayEffect FInheritedTagContainer properties or higher up: a UObject CDO's PostLoad and a UObject's CDO being invoked by a subclass on the loading thread.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-166872 in the post.