Permanent offset on bone for no apparent reason

I was experimenting with adjusting bone rotations and IK solver in Animation blueprint so that character hands could fit the gun but something went terribly wrong and now there’s permanent translation offset on the left hand bone.
I’ve bypassed all the bone manipulation nodes and feeding plain animation to output but it’s still there. It doens’t show up on skeleton asset but its’ on every animation sequence and in animation blueprint preview.
Anyone knows how to undo it?

image upload doesn’t work for some reason

Seems that the reason was retarget pose not being in perfect alignment with target skeleton pose (was importing from the AnimationStarterPack btw, skeleton wasn’t compatible with 4.18 for some reason)