You’d likely want to attach the DefaultSceneRoot in your TestGrab bp to the LeftHandMesh component instead of your actor using AttachToComponent. The actual hand actor doesn’t move, but the hand skeletal mesh component and its children do.
Looking at the code https://.com//leap-ue4/…erList.cpp#L70 that analysis does appear to be correct. Probably the best workaround would be to fetch the direction and store it in a local variable like you said, then do the final comparison with the stored local variables instead of directly referencing the fingers. This may have been a case of me marking a blueprint function pure, when it shouldn’t have. This shouldn’t be an issue in the preview plugin as it uses structs to hold all the data.