Blueprint crashes on open level

I’m getting this error whenever I try to open a level using a trigger volume. I don’t have anything special in the maps, just a couple static objects, no UI elements or anything.

Fatal error: [File:D:/Build/++UE4/Sync/Engine/Source/Editor/UnrealEd/Private/EditorEngine.cpp] [Line: 6986] Previously active world /Game/UEDPIE_0_intro.intro not cleaned up by garbage collection! Referenced by: (root) UnrealEdEngine /Engine/Transient.UnrealEdEngine_0->Trans TransBuffer /Engine/Transient.TransBuffer_0::AddReferencedObjects() (PendingKill) World /Game/UEDPIE_0_intro.intro