Custom armature'd object appears shriveled

hi! i asked about this is a discord server but figured i may as well make a post here - so if i get a solution i can refer back to it later ^^

here's my problem;

i'm attempting to convert the pokemon bulbasaur's model to the sims 4, however, instead of being a static object, it's animated using a custom armature

i've been able to 'successfully' create the custom skeleton in S4S and rig bulbasaur to it, with the help of pancake1's rig exporter. this is what it looks like in S4S

however, in game, while it would appear the rig carried over, anything that is rigged is shriveled

(the bulb is intact as it was not rigged)

i'm not sure if it's the bones or weight painting that's the issue here, but i can't figure this one out

here's the package file if anyone wants to take a look (discord hosted link). the object's interactions depend on an external package but it shouldn't be an issue i hope