Ok. That will just be the well known problem where set point changes are sometimes reverted by the HR92's hourly set point broadcast.
Had that happen to me a couple of days ago - we had a visitor staying the night in the living room, which is scheduled to go from 20.5 degrees to 5 degrees at 11pm, at about 11:30 they were ready for bed, the zone set point had already gone to 5 but the room was still warm of course, I used my phone to set a 19 degree override until 9am the following morning for them then went to bed myself.
The next morning I came down to find the living room sitting at 15 degrees with a 5 degree set point and a manual override end time of 9am. Argh....
Their radiator had been off all night because the set point reverted back to 5 degrees just a few minutes after I changed it and I wasn't around to notice. I even see the evidence of it in my graph where the set point briefly went up to 19 then back down to 5 just a few minutes later.
Will we ever see this problem fixed I wonder...
For me, it's been there (very infrequently) ever since the very first firmware update that added local override display, over 2 years ago.