[BUG?] BP Variable showing as blank in Animation BP

So I was doing some basic set up for an animation state machine when I have run into an interesting problem. Whenever I’m dragging a variable from any other Blueprint into an animation Blueprint it shows up as completely blank. For some more info this variable ‘leftMouse’ is created in C++ like:

UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "CharacterVars") bool leftMouse;

However any other variable just created in the Blueprint editor will also give the same results. Using those variables in their own blueprints has them displaying perfectly fine.

17683-bug.png

We’re using a build of UE4 (4.3.1 iirc) compiled from source so we can make modifications to certain parts of the engine if that helps at all. If I haven’t set this up properly or am missing something it’d be great to know.

Thanks!