hi,
Ive looked a few times.!
If you pause the video about the reset time, you are clearing the hours but the mins/secs are still showing 59:59.
After the 59:59 clears to 00:00 the hours units is set to a '1'.
I would try a an R/C delay into the hours units reset line, make it reset until the 59:59 becomes 00:00.
we expect 01-00 after an hour after, 12mid night or 12 afternoon. How ever, I wonder whether the gates U17A and U17B are really needed and have a function? even the am/pm indicator not needed as one knows whether it is day or night, unless it has calender display with day of week & date.