Star Trek VI: The Undiscovered Country - Shoddy Timekeeping
On the bridge of the Enterprise, you may notice a red LED 'clock' behind the actors, just above head height. If you watch carefully, the time displayed jumps about all over the place! (Note: I know stardates are supposed to be relative to position and speed of the ship in the universe etc. but the ship is stationary.)
There's nothing shoddy about the time keeping... because the red LED is a 24 hour clock with hours, minutes and seconds. That's why it's always changing cause last time I checked, time doesn't stop just because you're standing still.
The clock times do seem to be somewhat inconsistent. However, the slip-ups are only noticeable if you write the times down each scene, then review them. If you just watch the movie, they are not noticeable.