Why are horizontal stripes visible only on a blue background at high hertz (from 60)?

Question

Monitors

Greetings.
Monitor CU34G2X, Windows 10, all current firewood

Problem - classic light blue color is selected for windows. Selecting Hertz >60 (100, 120, 144) causes horizontal stripes to appear on the blue top of the window frame (Explorer, Chrome).
If you move the window around the screen - they are less noticeable in the middle, they are practically invisible from below.
They are transparent, at a very close distance from each other and very noticeable at 50-60 cm from the monitor.
When there are several tabs, the small text on them is also distorted a little.

In the summer I changed the color scheme of Windows and the fill in Chrome and scored.
Now again I decided to google what is the reason and found a mention of the problem at least 3 times

spoiler

forum.3dnews.ru/showthread.php?t=142458
https://www.cyberforum.ru/monitors/thread2225566.h...
forum.3dnews.ru/showthread.php?t=139148

Now (half a year after the purchase) I thought of checking it at 60 Hz - and a miracle, there are no problems with this hertz.
The video card is not 100% guilty - in the spring it was 2080 Ti, now 1050 Ti.

I did not take it to the SC. appears only on a blue background (in my use it can be considered never).
Actually the question is why, at a high frequency, such interference in the upper part can be attributed to the SC with such a reason?
Thanks