Hej everybody, and god nytar!
I have a v7 upgraded to "android only" control (SW 1.174). I discovered the problem around 0:45 this morning. In my case, there were a lot of entries Power -> DHW (and vice versa) in the event log, all at 0:00, and an (incorrect) message "Info: Over 10 ignitions in 24 hours".
I tried a few things including restarting the pillefyr (which may be part of the solution; it now thinks it's 1 Jan 2030 and the clock is permanently set to 0:00). I also took DHW out of the equation (by lowering the DWH target temperature to 10°). The system behaved normally thereafter in "Power" mode. I then deactivated the DHW timer and tried DHW production again this morning - everything seems to work now (the pillefyr has always been connected to the internet).
The only irregularities now are (1) the wrong "Info: Over 10 ignitions in 24 hours" is still showing (both on the app and the web interface), (2)the app does not produce any usable charts (but the web interface does), (3) can't draw an event log via the app (but drawing via web interface works), (4) permanent date/time 1 Jan 2030 0:00 (except that charts via the web interfact produce normal data for some reason).