Check-in app "scanning in progress"

Hi, frequently users are receiving the message ¨scanning in progress¨ after just scanning a QR in the Indico check-in app for IOS, preventing new scans. Any ideas on what could be the cause of the problem???. Thanks for your replies!

Never heard of it. Is it breaking the app or just annoying?

Thanks for four reply. Some times after restarting the app, it continues working, but some others after scanning just one QR it stops again.

But once you get that message the app crashes?

Yes, it simply stops working. I´ll try to reproduce the problem and post a pict.

Here some examples of the problem. In our case we have events around the world so users go and come from different locations. Seems like It happens when scan is made for multiple events at the same time or the event coordinator has used the app for a previous event. Maybe the developers of the app have a clue of what could be the source of the problem and help us to prevent it. Thanks in advance for your replies!.