Google calendar off by timezone [not relevant]
The entries imported from my google calendar show as one hour later than they are. E.g. an event set for 0815 in google calendar shows up as scheduled for 0915 on the phone.
My timezone is set in the google calendar general settings and google says it converts and stores events in UTC. Jolla then appears not to convert these back to my timezone when displaying events.
I've edited some events to have an explicitly set timezone, but I'm not sure how often Jolla syncs to the calendar. (I also added a dummy event to test, which as of the time of writing hasn't shown up yet.)
Edit: The problem went away. I don't know what caused it, and I don't know what fixed it.