I'd instead ask them to show which monitor they are using. Windows 7, 8, 8.1 and 10 will all display everything on whichever monitor is plugged in, regardless of GPU attached. It looks like the game recognizes it's running on the >60hz monitor, but the vsync setting is locked to the OS setting.

https://www.reddit.com/r/pcmasterrac...ith_different/
Next go to your nvidia control panel and click on adjust desktop size and resolution.Set both your monitors to "Perform Scaling on" to your GPU and not the display which is the default.
There are two other options you can consider as well:
- Use the iGPU (you may have to turn it on) to run the second monitor and plug it physically into that one
- Use two identical monitors (or at least two monitors with the same frequency multipliers

The third option is to unplug the 60hz monitor.