I never follow links outside of GL into the app. I always start it from the Android home screen using the app button.
1-4. No matter how many screens I create and which ones I go to and exit from, the app always opens at Screen A, the first one, and not at any other screen from which I departed the app. This duplicates what you saw in steps 1-4.
5-8. I did not see exactly what you saw. I believe these steps and steps 9-10 happen because of what I discovered next. I'll come back.
I have discovered that the problem triggers when you delete the active screen, which is shown with a narrow underline in the Screens screen. If you go to Screens and delete the screen from which you came, you do not even need to exit the app. Press the left arrow to go back to the screen you just deleted (it is still there), then press the Bookmark/Screens menu button to see two new screens have been added. You can toggle back and forth from deleted screen to Screens display and add two blanks each time. (I did not test to see how many screens you can have, but I'll bet I could find out quickly enough unless the app crashes first. It would be a pain to count them, though.)
I am able to trigger the same action by using the Close All Screens line in the overflow menu. I imagine Close All Screens uses the same code as the Delete function on the individual screens with the same exciting results.
Back at 5-8 and 9-10. When you exit the app and restart it, it is trying to open Screen A which was deleted. Hence, two more screens for the collection.
There is a display issue that may be related. When I say two blank screens are added, they are blank, but they have the title at the bottom. Pressing them takes you to the appropriately titled screen, and when you return to the Screens screen, they display the page as you would normally expect, rather than a blank tile. This display issue happens independently from the two extra screens.
So it seems to me that deleting the active screen causes the Screens display (and code) to go berserk.
I am trying to figure out how I am personally triggering this problem. I rarely use multiple screens, but sometimes I do. And when I do, I have a habit of cleaning up the extra screens. In that process, I have probably deleted the active screen. Even though I go from Screens back to the GL home page, I can see where I may have triggered the bug and sent GL off the rails.
Isn't this fun?
I sent a brief bug report and mentioned this topic.