Basically if in blueprints 2 nodes are connected in a loop and you right-click and click on ‘select all output nodes’ it causes a crash. In VS it says it is a stack overflow error.
It is a bit annoying if you want to right-click break connection but miss-click on it and the editor crashes!
I’ve reproduced your issue, but it appears to be fixed in 4.15. The corresponding ticket is UE-38988. Unfortunately, the ticket contains sensitive information and cannot be made public.