[Nouveau] unstable refresh rate

[James]

I have a Gigabyte GeForce 1050 connected by DVI to a monitor (1920x1200 
resolution @ 59.9502 Hz) and a TV via HDMI (3840x2160 @30 Hz).
The problem is the TV used  to work at 59.9685 Hz but then it started 
showing "No signal" on the TV.
I was changing settings trying to get it to work again and I happened to 
change it to 30Hz and it worked.
The specs are here:
https://www.gigabyte.com/Graphics-Card/GV-N1050OC-2GD/sp#sp
 >Digital max resolution: 7680x4320
I should be ok resolution wise.
Could it be a poor cable?
kernel: 5.0.0-23-generic