When I morph into any flying mob, it always moves by itself. Here are the mods i have, im not sure if one of these mods is causing the issue.
https://user-images.githubusercontent.com/39245952/39970940-7f84246c-56c1-11e8-8986-ade7425f3b13.PNG

#878

I am having this issue too! Running 1.12.2-7.1.2