Have you seen this from r105's log :
Sprite: 'set animation' in an 'on animation finished' event did not always have the intended effect
Do you happen to use such setup ? Perhaps your code war running whereas it shouldn't have.
I've opened projects made with r105 and/or r104 (I'm sure tbh) and with animations working on preview.
It sounds more like some changes/reorganisation to your code might fix this.
Can you confirm if it happens also in a new project ?