They are both correct. Do not change anything. The 59Hz is normal in Windows 10. The notation changes nothing in the performance of the monitor. In previous version of Windows, Microsoft would round 59Hz to 60Hz.

I ask about the optimal settings as the desktop PC has some problems after turning on from the power saving mode or sleep.
Some of the program Windows that are maximized are resized.
It's very annoying that I often have to maximize windows after the system wakes up.
I believe that this may be due to the loss of information about the resolution and the refresh rate of the desktop.
Before the P2715Q UHD monitor I had 1920x1080 HP monitor.
There was no problem at all.
Once installed P2715Q UHD monitor so immediately there are many problems.
Moreover, in a clean system without installed Intel drivers for HD graphics, the monitor has much less problems.
At this point, I believe there are compatibility issues between the Intel software and the P2715Q monitor.
That's why I'm looking for perfect settings and detailed explanations of the nuances of the settings.