I've noticed pretty weird bug. So far it happened 2 times.
First time when I changed user virtual currency, his next call to custom Cloud Script didn't do what it suppose to.
Second time was even worse, new player made an account, I've opened his profile in the dashboard and forgot to close it. In the next 3 mins this user reports to me that his tutorial never ends - what happened is his title data (tutorial_finished: true) was not changing. This is the one and only user that had this issue since game released so it makes me believe that there wasn't a problem in my code.
This issue also made opening player PlayStream scary as there is a chance that something will break.
I will try to test it myself to find a way to reproduce this bug if I find some free time.