[Ionic push] How often is PushToken refreshed for the same device?


I’m using Ionic Push with Ionic 2. After calling registerToken() then saveToken(), a token is returned by the Ionic push API. I then save this token in my own database linked to my own user auth system. But the token returned by those methods seems to change very often at app restart for the same device.

So my question is : When the PushToken changes for the same method call on the same device ? Is it a normal behavior to check all previous token with GET /tokens/:id to see if valid property is false ?