Gimbal lock issues during a blendspace

Hi! I think I have a Gimbal lock issues in a locomotion blendspace.
Its during the blend between my walk animation and run animation. The two animations work very well but when the blend of the two is around 50%, the forearms of my character operate a sudden rotation. I tried several options for importing animations but nothing worked.

https://i.gyazo.com/d59ec6d9dc2ebd2b64393864e5eea0f2.mp4

Thanks for helping!