Jolla takes a deep sleeps, and timers are running but they run sloooow.
I have 1 second timers which takes sometimes about 2 minutes to trigger.
Your 5 minute timer can be many hours in worst case.

It is possible to trigger timer e.g. every 1s, and check how long time it has gone from the last trigger, if it is about 5 minutes, make your update.

EDIT: Just checked from my logfile, that maximum duration for 1-sec timer was 7 min 32 seconds. But the above approach is maybe accurate enough for updating sports results?