Occasional low contrast on external display when waking MacBook Pro from sleep

I've been using the LG 43UN700-B for a few weeks now. It's connected to a 16" MacBook Pro (running 10.15.5) for power and video via the USB-C cable that came with the display. Right from the start, I've been experiencing occasional color glitches. Every 3rd or 4th time I wake the MacBook from sleep, the external display will show very low contrast (like a gray filter applied to the whole image). The MacBook's built-in display is unaffected. Most times, I can get back to normal colors by temporarily changing the external monitor's resolution. Any ideas what could be causing this and how to fix it permanently? I was unable to find any firmware updates for this display.