It’s not probably breaking, to verify this you could put a print after the load stream level node, to see if it’s actually breaking the loop. What I think it’s happening is this:
If you check the link to the unreal documentation for this node: https://docs.unrealengine.com/latest/INT/BlueprintAPI/Game/LoadStreamLevel/index.html
It says:
Stream the level with the LevelName ; Calling again before it finishes has no effect
So maybe that’s the problem, the loop is going too fast and the node doesn’t get enough time to finish.