sessionStorage cleaned up unexpectedly on Android

I have a website which saves a stringified JavaScript object into the sessionStorage. It works well on desktop browsers - data survives over page reloads as per described on MDN.

On Android phones, it is not uncommon that a tab is reloaded when user switches back from another tab or when the browser is brought back from background to foreground, and I expect the sessionStorage will persist. This doesn't however seem to be the case. The sessionStorage is gone missing, as if a new session is created.

I have thought of using localStorage instead, which will not expire even if the session is closed. It doesn't really sort out all my problems though - as I expect a user can open it multiple times on multiple tabs, and do different things on each of them.

So my questions are:

1. Is the sessionStorage behavior described above as expected? If not, what can I do to rectify it?
2. If the behavior is as expected, and I have to rely on localStorage, how can I identify the object stored for each individual tab?

Thanks in advance for your help!

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