Suppose that, while #spine_model is playing ANIMATION_1, I play ANIMATION_2 with the following line of code
spine.play_anim("#spine_model", "ANIMATION_2", go.PLAYBACK_ONCE_FORWARD, { blend_factor = 0.1 }, Callback)
It seems to me that Callback is called ONLY when ANIMATION_1 is done and Callback is NOT called when ANIMATION_2 is done.
If I remove the blend_factor, then the Callback is called whit ANIMATION_2 done event.
I hope I have been able to explain myself…