It is possible to continue playing a deck that has 3 losses in a limited event.

Reproduction:
1. draft and build deck.
2. open arena on PC with the event page open, i.e. with the win/loss counter visible and play button in bottom right.
3. without closing app on PC, open arena on mobile with the same account.
4. Play until 3 losses
5. press "reconnect" on PC arena app
6. The cached version of the page is displayed, with amount of losses and wins present as when cached.
7. Pressing play puts you into queue
8. it is possible to achieve 4 losses (see attachment) with this, increase the amount of prizes, and I presume get 8 wins but I haven't tried that.

This is highly exploitable and a bad actor could take further advantage of abusing these stale clientside states. This is likely a very high priority issue and should be resolved asap