Happened for me too, twice now. Once yesterday, and today.
Yesterday I was told the phone number hasn't been used in the past 90 days. Today I just got logged out, having to enter my account credentials again. I don't use the app on another phone, nor do I use the API at this moment.
I did contact support, which told me the report will be passed on to developers.
Also using an Android phone running Android 7.1.2 (Resurrection Remix, rooted).