Question: 4k display randomly uses 30Hz instead of 60Hz
I'm using an LG 27UD68 4k external display with my mid 2017 Macbook Pro and an USB-C - DisplayPort cable. The display works well most of the time, but sometimes when my mac wakes from sleep it is using 30Hz instead of 60Hz.
In order to fix it I have to turn off the monitor, unplug the USB-C cable, plug it back to a different port and turn the monitor back on, and I usually need to repeat these steps a couple of times. I already did an NVRAM and SMC reset without any luck, detecting displays when the issue occurs also does nothing. I had no such issues with macOS 10.12, it started after upgrading to High Sierra.
Is there a permanent solution for this? Having to spend a couple of minutes with this roughly every 3rd time when my mac wakes from sleep is extremely annoying.
MacBook Pro with Retina display, macOS High Sierra (10.13.2)