Hi
You’ll get one “ticket aztec code” per activated travel day. just activate several trains, and then open your ticket and scroll down. you’ll see all trains listed that you activated.
There is only one known bug about this: IR app doesnt has live data, and expects all trains to be on time, and restricts from having “two travels at the same time”. so, if you get a connection to a delayed train, which planned departure was before your arrivel at the station where you changed, it wont allow you to check in the new train…
Yes, as @runner.on.rails says, you’ll get a QR code when you toggle the switch to show that you’re taking a train. And that train will be listed below the ticket.
If you’re taking more trains, they will also appear below the QR code, you can activate them whenever you like. But the code itself won’t change. It just contains basic information about you having a valid pass, the type, the expiry, your ID details. But not anything to do with your specific trains I think.