Monterey 12.6 - LG UltraFine 4K Display Dropping From 60Hz To 30Hz After Sleep

OK, so I finally solved the problem. 😅✅

It wasn't the cable (I'm still using the same one). It was actually the port on my LG 23.7" UltraFine 4K Monitor.

The LG 23.7" UltraFine 4K has two Thunderbolt 3 ports. All I did was move the Thunderbolt 3 cable from one port to the other. And somehow that fixed it.

So, if you're experiencing the same problem, trying plugging the cable into different ports. I don't know why it makes a difference, but somehow it does. 🤷🏻‍♂️😂

Thank you for replying. 😊

I've just downloaded the LG Screen Manager app, but surprisingly it has no settings for the monitor (other than Factory Reset). Also, if I select Monitor Update and click on Update it tells me that "the software is currently up to date".

I'm using the official LG cable that came with the monitor. Why would the cable not have any issues with Catalina and Big Sur but then suddenly have one with Monterey? I'll try disconnecting it and plugging it into a different Thunderbolt 3 port to see if that makes a difference.

I turned off my Mac mini, unplugged the Thunderbolt cable and plugged it into a different Thunderbolt 3 port on my Mac mini (which has four Thunderbolt 3 ports), and restarted my Mac mini.

Initially it was fine (running at 60Hz again) but when I put it to sleep for about 1 minute and woke it up again, the refresh rate had dropped back down to 30Hz. ☹️

And when I go into System Preferences > Displays, there's no option for Refresh Rate so it's not like I can change it manually. The only way I can get it back to 60Hz is to restart my Mac mini.