Blueprint actor component properties do not automatically flush dormancy when set

UK2Node_VariableSet::ShouldFlushDormancyOnSet only returns true for classes that derive from AActor. This leads to inconsistent behavior, as the owning actor will not have FlushNetDormancy called on it when a replicated property on one of its components is set.

Create replicated actor and actor component blueprints, each with a replicated property.
When changing the actor's property, FlushNetDormancy will be called, but when changing the component's property, dormancy is not flushed.