Leaving Tor Browser with back button closes all tabs

When you load a new tab from an external app, then close it with back button, it closes all tabs. It should only close this tab. It is really annoying when you set Tor as the default Browser because you have to take care everytime

Steps to reproduce:

1. Open Tor Browser
2. Open a tab
3. Leave tor (Home button)
4. Open a tab from an external app (e.g. by sharing a link to Tor, or if Tor is the default Browser).
5. Close this tab with the back button

Expected:
Only the last tab is closed. It's the behavior in Firefox, Chrome.

Actual:
All tabs are closed. When you open Tor Browser again, there is the connect screen.

I'm not sure though what is expected to happen if it's the last tab. I.e. open tor, leave tor, open a link from another app, press back button. When you open Tor Browser again, should we see the connect screen or the homepage with 0 tabs opened?

Version: 10.0.5