Nate yazdıIt's hard to tell what might be going wrong in cocos. 3.5.51 is quite old, more than 4 years ago. It could be there is a bug with how AnimationState is applying animations, or it could be the runtimes are so old that they are before we changed how animations are applied (I just explained it minutes ago, here). Can you use the 3.8 or 4.0 runtimes?
Nate thank u for your reply.
We are using older version of cocos that doesnt support spine animation higher version.
And I found out that the problem was not caused by bug. it was caused by some "draw order keys" or "show&hide slots keys" at the end of some animation.
Like the picture attached down below, if I hide my face,eyes,eyelashes and eye skins at the first frame when I'm animating a back animation, should I reveal them at the end? Because if I dont, these image will be missing when I turn my character from back to front.
So my question is is there a rule if we should reveal these hidden image at the end frame if we want to use trackIndex to merge animations in cocos?