S2721Q display issues through HDMI

Hello,

I have two XPS 8930 desktops sharing two S2721Q monitors. The resolution is set up to 4K resolution. 

Computer 01 (GTX 1080): monitors connected via Display Port

Computer02 (GTX 1070): monitors connected via HDMI

Computer 01 is working fine, however, on computer 02, the monitor looks weird. The colours look like the RGB are offset. This issue goes away only when I change the refresh rate from 60Hz to 30Hz. 

If I interchange the cables, the issue happens to computer 01, and then computer 02 works fine. 

At first, I discarded a problem with the cables and/or video card because I tested with a DVI cable and happened the same problem. All drivers are up to date.

Any thoughts? Has anyone gone through a similar situation?

Thanks,

Renato