Dual monitors keeps on blinking after wake

[Gorian1]

I'm having a strange problem. I'm running a dual monitor setup, and whenever I have my second monitor hooked up, the monitors keeps on blinking after wake from (what I guess is) deep sleep. It only happens if I have my second monitor plugged in. With just the one monitor, it works fine. The only way to resolve the issue is to shutdown or reboot the computer.

I didn't use to have this problem, and I'm not sure as to what has caused it.
I'm running Mojave 10.14.5.

Here is a video showing the phenomenon:

What I've tried so far:
1) Replaced the HDMI cable to the secondary monitor.
2) Switched HDMI/DP ports on the GPU.
3) Replaced the secondary monitor with a new one (), as I figured the old one was broken.
4) Updated Lilu and WhateverGreen using Hackintool.

Any ideas?

 

[Gorian1]

Anyone got any ideas? Could really use the help. :/