I have an 810 recent full service...always "seemed" to be working properly to I can't say I ever let the chronograph run all that long, and if I did I never really paid that close attention to it.
This morning I gave it a full wind and started the chronograph up, mostly because of the reading I have done about the new 01 movement and chrono issues and just wanted to see what mine does on long runs. Looked at it well into the day and it was close to the 2 hour mark. Can't really say it if was 1.5 or 2.5 but for sure more than 1 hour and less than 3. I thought it should be more along the 4 or 5 hour mark. Been watching it more closely and I know it was just at 1.5 hour mark with the 30 minutes sub working its way up from 27, 28, 29....when it got to 30 the hour marker hand did not move...I thought okay it won't till it gets another minute in and actually reads an additional 31 not 30 minutes. That did not seem right but I was letting it go. I did not stare at it for an entire minute but when I looked back the chrono hand (not small second hand) was at about 45 seconds and the hour totalizer was at 0.5 hours
Surely it had moved backwards or forwad a long jump.So I stopped the chrono, reset it to all zeros at just about 4:30PM and now just about 10 minutes later the hour totalizer is nearing the 12 hour mark reading 11.5.
I never see the actual hour totalizer move, but quite sure it not acting as it should. Picture below is after it ran for about 10 minutes from 4:30 to 4:40 when I stopped the chrono functions but did not reset it. Note the hour hand has kept moving to the 4:42 mark as it should but hour totalizer is at 11.5
Hope I am explaining this clearly. Basically, I am sure the chrono ran for the better part of 4-6 hours but twice it was reading in the 1.5 hour range. When I watched it more closely after just about 10 minutes it was at the 11.5 hour mark.
