I wonder if this is a graphics card issue. Could you try disabling GPU usage and see if it helps?
Go to Lightroom's Preferences, and under Performance, disable the option to use graphics processor. Let us know if that helps.
Nope that wasn't it.
What type of computer are you using, Mac or Windows?
What operating system is installed?
How much RAM is installed?
Could be a defective monitor profile.
Try setting the monitor profile to sRGB as described here: How do I change my monitor profile to check whether it’s corrupted?
If this fixes the issue, you should ideally calibrate your monitor with a hardware calibrator.