When i morph and disable mob hostility is true, the hostile mobs still attack me.

disable_morph_disguise should be set to false in order to prevent mob hostility. Change it back.

Once disable_morph_disguise is set to true, are you still having the issue? If so, for what morphs? You may have to change your morphs.json, especially if you are noticing the issue with non-vanilla morphs. Check this guide for how to do that.