Yesterday morning I switched over to non-freesat mode to watch Bloomberg for a few minutes. I turned the box off and headed off to work.
When I returned, I switched the box back to freesat mode and checked that all my scheduled reservations were in place. They were! I left the box switched on and when I later returned to it I found that the first two scheduled recordings had been completely missed. They were still there in the schedule but the time had passed.
I can only conclude that if you switch from freesat mode to non-freesat mode and then back again, you must have been back into standby and rebooted in freesat mode for the scheduling to continue. That's what worked for me. I turned it off and sure enough the next recording worked as expected.
I looked in the schedule later and the two that had been missed were now gone but new reservations had been set for the next programme in the series.
I've not had chance to replicate this so it could be user error!