No idea.

I took part in Turf Skåne’s event Nyårslöfte today. 15 minutes (15:15) before the end of the event, I got the ten second countdown followed by the message Event Finished. I could still see the event zones, take them and lose them (even after restarting the app). However the top bar switched to showing my normal score. If I opened my user board (the window showing rank and zones owned etc. in the app), it only showed the event zones. I also had access to the event scoreboard. When the event did end at 15:30 I got the Event Finished message, but no countdown.