To save screen space, I no longer use the clock in status bar. I use the clock provided in Status Bar Mini PRO, and it appears to be accurate. The only rub is when the machine is closed and asleep, Status Bar Mini PRO must take a second to generate the proper time (the app must go to sleep, too, I guess).
Since SBMP merely gets its info from the Gemini, I wonder if the time is always correct in the Gemini, but loses itself during the process of its display.
For testing purposes, there's a free version of SBMP, which can place a simple text clock anywhere you want, and it'd be interesting to see the results of the SBMP clock vs Nougat's own.
Jake