3.8 is very old, we haven't made fixes to it for many years. It could be a bug in 3.8.
Does it work correctly if you don't use animation clean up?
Coco Creator must have a runtime, else Spine skeletons couldn't be displayed at all. If you are using a runtime that came with it, maybe you can replace their runtime with ours, like could be done with cocos2d-x. If not, then it may be a bug in Coco Creator or the runtime it uses.