I checked here setting up the contest for today at 1700z and the QSO numbering works as it should. At each ten minute mark, the stations in the bandmap that I entered as working in the previous 10 minute section change color to workable again. The next sent number does NOT get set back to 1. I am using v.1.0.7149.0, but I doubt that would make any difference.
I cannot explain why it did not work for you. Did it reset the SntNr every 10 minutes, or was this just a single instance?
Perhaps you could try it again now and make some fake QSOs by entering callsigns and serial numbers and using the log button to log the qso. That way the radio does not have to transmit. Does it still reset the sent number every 10 minutes?