No idea if this is related to Erdrik’s problem, but for anyone else who may be reading this: If you are getting an access violation on tset FindID(), make sure you are not modifying a TMap while iterating over its contents.
UE4Editor_9862!TSet<TTuple<FName,int>,TDefaultMapHashableKeyFuncs<FName,int,0>,FDefaultSetAllocator>::FindId() [s:\programs\epic games\ue_4.18\engine\source\runtime\core\public\containers\set.h:629]