What do you have the MacBook Pro plugged into? Are you using the Apple AV Adapter with HDMI? If so, I had the EXACT same issues with my LG 29" UltraWide display and said adapter. Ultimately I couldn't find a fix for it.
What do you have the MacBook Pro plugged into? Are you using the Apple AV Adapter with HDMI? If so, I had the EXACT same issues with my LG 29" UltraWide display and said adapter. Ultimately I couldn't find a fix for it.