Basically a duplicate #84 but I'm not running a cracked server, nor do I have the extra addon the other poster had.
I'm using v1.16.5-8 on the modpack All of Fabric 3
https://mclo.gs/LlIvt5i

Normal Form:

Werewolf Form:

Everybody else can see me as a werewolf, only I see myself as a stretched human. For some reason the bug fixed itself when I changed my skin but it came back after I closed my game.

This isn't a problem on 1.16.5-11, All of Fabric uses an old version so you should ask them or wait for them to update