That is absolutely not the problem, and this issue remains unresolved (but I’m not allowed to un-accept this answer). If you’ll look more carefully at the screenshot, there is a sequence node which first calls the if statement and then hits the return node. Disconnected return nodes cause blueprint compiler errors, not windowless engine crashes.
Even with every execution pin connecting explicitly to the return node (see the attached “Still Broken.png”), it still crashes with an “Unreal Engine has stopped working…” dialog (“Hard Crash.png”).
This has to be a bug in UE 4.8, since it worked fine in 4.7.
