Weird "straightning" of body when jumping/falling

Good afternoon, so long story short i started trying to customize my avs with texture and clothes. But idk why they do a weird straight pose when jumping/faling. I only have a vid to really show what happens, but in short it does a weird straight upwards move (idk if i can post links here, but i have the streammable thingy vid to show )

pretty sure you can post links here, i was able to. send the video please