Question What's causing my monitor to occasionally flicker/glitch?

Jun 18, 2020
My monitor often glitches on the bottom part to which I could not isolate the cause. I have updated my graphics card driver and even install the latest driver for the monitor. The native resolution of the monitor is 1366 x 768 @ 60Hz. Sometimes whenever I start my computer it sets its resolution to 1280x1024 @ 75Hz. The glitch rarely appears but when it does, it's just a line.

I don't know what's causing the problem. Can I force my monitor to increase its refresh rate as 75Hz seems to remove it?

I'm using a laptop and the monitor acts as a secondary display. The monitor only has a VGA connector and have to use a VGA to HDMI adapter as my laptop only has an HDMI port.

My laptop's resolution is 1366x768 @ 60Hz with Intel HD 3000 graphics.
The monitor is an HP LE1851w.

Here's a link to a video showing the display flicker: