this is most likely not 3.8's fault
with arm textures, you have to mirror and offset one of them
in this case the left arm looks to be fine, so you'd mirror the right arm
to do this:
-you first offset the texture by 32 pixels (this is if its made in 128x128 )
-after you flip the picture horizontally
that should make it even
(correct me if i messed up, im tired :P)