Out of curiosity, did you check the models for the armour "sleeves" too?
It could well be something more subtle, like (some) of the "sleeve" models being weighted for skeleton with bones indexed in different order and so winding up incorrectly weighted when the game puts the data together. Impossible to say without knowing exactly how the game stores/reads/combines/interprets these things.
yes theres something weird about upper arm being rigged in a different order than bones linked,but since every mesh (nude body, slevees,etc) and human(female) does not have problems like other race does ,i doubt its something related to rigging.
one thing is really odd that i dont have any idea where male human skleton located . nd i dont want to make suggestions about that problem we have, im not even near to consider myself pro, so its better for developers to do their job they know better.
totally agree the problem could be in code, skeleton or animations. but theres a tool which reads data files and can export skeleton properly and order bones linked is the same in every skeleton for any race ,gender.only joints positions are different( and mybe scaling) .
idk
edit --------- hierarchy seems to be fine, nvm about order, makes sense to me now, my bad. 
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Tried to export human model using elven skeleton, got weirdly skinned mesh ( not symmetrical, left arm rigged to other bones, not like right arm)
Also, when i was looking for other rigged stuff, there's a bone called UpperArmQuat_GS (shoulder area) and some meshes have vertices weighted to it ( in human male, elven female, human female, Abelas, Calpernia models) some not (elven male body, few elven male sleeve meshes, didnt check for different races/parts ). i'm lost. and sleepy, will check later if i have mood to do so, it's really bothersome wandering thru every single sb file to find armour parts.
I'm not even sure if it's topic related. Kill me 
aaaaaaaaaaaand i am really sorry for my english, i am so sleepy typing this wall of text and so tired checking stuff, my brain is kinda slow, very slow.