Windows 8/8.1/10 Monitor "flicker" in Crimsonwood Keep

Description of the problem:
When moving around quickly in Crimsonwood Keep, the outside of the active client flickers with a light-green overlay. To be clear, it's not a flicker as in the screen turns on and off. The flicker appears like very fine diagonal light-green lines across the entire screen, excluding the active client.

Some things that I've tested to try to isolate the cause (note: any mention of "screen" refers to my physical monitor screen, not the ML window):

• This happens only on the HD client:
  • 800x600 and 1024x768 does not have this issue.
• This happens in very specific locations:
  • Any of the monster maps: Tornado Corridor, The Inferno Chamber, The Wrath of Night, Stormhall
  • The stairs right outside the door to Hall to Inner Sanctum
    • It's all okay if my character is underneath the stairs, or to the right of the stairs right outside the door (this part is most confusing to me).
  • The Courtyard, remainder of Hall of Mastery, and Hall of Inner Sanctum, all do not have this issue.
• It happens anytime there is significant movement on-screen. I know this because:
  • Walking left and right, nothing happens.
  • Teleporting triggers the flickers.
  • Jumping down the map from a height triggers the flickers.
  • Moving the window around triggers the flickers.
  • I tried all of these on 2 different mage characters.
• The overlay appears on everything besides the active client.
  • It appears over all other windows behind the currently-active client.
  • It appears over all other MapleLegends clients that are not in-focus.
  • It appears only on my primary monitor.
• I have had this issue before this patch. I didn't report anything then as I was hoping it's just a one-off.
• This may be a hardware issue:
  • This happens only on my primary monitor, and not my secondary monitor (though both are using the same GPU).
    • The flickers only ever appear on the primary monitor when >60% of the window is within the primary monitor. The flickers are not triggered when majority of the window is on my secondary monitor.
      
    • Moving around on the secondary monitor does not trigger any flickers on the primary monitor.
  • The flickers still appear even when my secondary monitor is turned off.

Extra information:

• Primary Monitor: MSI Optix MAG27C
• GPU: NVIDIA Geforce RTX 2060
• OS: Windows 10 Home 64-bit
• CPU: Intel i7-8700 3.2GHz
• DirectX: 12

I realise that this is a very specific issue (only on one monitor, in a few maps, on HD) and possibly not worth trying to fix.

I am sharing this because there seems to be no mention of anything similar, and I'm curious if anyone else has encountered a similar issue. I am slightly worried that the root problem may cause other issues in the future.

Apologies for the wall of text, and thank you very much for reading all of that.