Something problematic with the blend mask and the animation blueprint

[WindyStrife]

i managed to fix it, cherry pick from 5.1 can u with 5.0, just using it for comercial game project.
or u can go to 5.1 to fix this
https://github.com/windystrife/UnrealEngine/commit/eef809b8d181c821caccede3208b1e3a9c70b956