Unable to use Mask ( B ) as input to If in MaterialFunction

When using this MaterialFunction and using anything but the default input on the Pos (Vector3) FunctionInput causes the If node to complain that the input A (Mask ( B )) is no longer of type float.

Isn’t that exactly what ComponentMask is for? To only have a single float out of a Vector? If I’m mistaken here, please correct me.

Screenshot of my node graph (for this MaterialFunction):

http://cdn.xaymar.com/private/UE4Editor_2016-02-27_22-41-52.png

(How do i take one of the entire graph?)

UE4 Version: 4.10 (if that’s necessary)

Edit: Okay, I may have already solved it, accidentally. This strange behaviour only happens if I use the output Pos_Out and connect it back to Pos without touching the initial Pos input. Bug?