Faint colour shifting in games

I'm not sure if this is down to my monitor or GPU, but when playing games, there will be a slight greenish yellowish tint to the display, as if the colour temperature and tint is intermittently changing. It's rather faint, but it is noticable.

I have a Dell S2419H monitor and an AMD RX580 8GB with the latest drivers. The monitor is connected via HDMI and I've already tried factory resetting the monitor and have ensured the HDMI connectors are firmly inserted.

Any ideas?

Try replacing the monitor. You could also try to remove the GPU and connect it to the onboard GPU