When calling PrimitiveComponent LineTraceComponent with FCollisionQueryParameters that enable bReturnFaceIndex it never actually return anything. If using similar lineTrace that trace against whole UWorld it does work.
Bug is related to this code line where InputParameter bReturnFaceIndex is hardcoded to false instead of using parameter passed to the function. https://github.com/EpicGames/UnrealEngine/blob/423874f59fab7d34f8ec2a0e18e4511f6ee0281d/Engine/Source/Runtime/Engine/Private/PhysicsEngine/BodyInstance.cpp#L4161