Android activity recreate itself

Question

My app normally works just fine, until I face a strange problem on specific device. There are 2 activities in App. After I start ActivityB inside of ActivityA, ActivityA starts

Answer 1

There's an Android developer setting called "Do not keep activities". The description for this option is "Destroy every activity as soon as the user leaves it." This sounds like a good description of what you're seeing, and since you're only seeing it on a few phones the idea that this is caused by a non-default system setting seems plausible.

Ideally your app would still work in this scenario, even if less optimally. But if this setting is a problem for your app, you may wish to document this problem for your users.