Yes, I should clarify though, this was for UE 4.10. Whatever magic was done for the 4.11 plugin has fixed the issue (it looks like mostly wrapping everything in UPROPERTY and modifying the private classes some). However in 4.10 all you have to do to replicate is:
>make a blank character
>add the leap interface
>add the “handsmoved” event node to the event graph
>from the LeapHand that is returned by the “handsmoved” node call “fingers”
>play and hold hand in front of face for ~1 minute
this should be enough to cause the crash as it happens specifically in the “setfingerlist” function when you say _private->fingers = fingers which is triggered on calling “fingers” from blueprint. If you’d like me to actually build a blueprint and post it here I can, but the steps are fairly simple.
Also, using Rift DK2 (I’ve tried plugging the leap into the headset and into the computer, doesn’t make a difference)
NOTE: We’ve moved to 4.11 anyway so it doesn’t really matter anymore I suppose (last post was before that decision was made). However this may still be useful information for people stuck on the older versions.