UE4 crushes when assigning rotation to bone

I get UE4 crashed after assigning a rotation to my head bone.
It was all fine before I’ve started using FInterpCurveVector class (vector curve). The class itself works fine for me, but after I take some values from it and use them to calculate rotation angle (in degrees) and apply that rotation to the bone, my UE4 crashes. I logged out all values from my calculations and rotation angle is 0 (I am now only tweaking my curve, so that’s fine). When I try to simulate the assignation of that value by assigning just 0 by hard-coding, it all works as a clock, but as soon as I let my curve assign it’s zero rotation value, crash comes.
I use c++ to set variable, which I then use in animation blueprint.

It only happens when the value is 0. If my curve tries to assign any rotation but 0, it works.

I found a way to avoid that problem, but it still exists. I also forgot to mention that it is not the first time I meet this problem so it is actually an issue.