I transferred yesterday - arrived c17:30 and had a mobile boarding pass for the 00:55 flight. I had to sit in the "transfer area" and eventually received my paper boarding pass (as CAI is unable to use mobile passes) at 23:10. Thankfully I had a book to read and was relatively relaxed. I was told that it was due to the recent transfer to Terminal 2 by Qatar.

One thing seems clear - the system seems to work on the time to boarding. Those transferring to other terminal and flights with shorter time periods did progress quicker.

So, a back to back maybe possible especially once Qatar have settled in to Terminal 2.