Question: High Sierra DisplayPort issues
So here's the situation:
2016 15" MacBook Pro
Dell P2715Q External montior
I've been using this monitor setup for about a year and a half. Since upgrading to High Sierra I have been experiencing issues. Using the laptop open and connected to the external display everything is totally fine. However, when I close the lid to use it in closed clamshell mode the computer freezes and I have to force reboot the computer. Sometimes the external screen will show a bright red color. I am using a USB-C to DisplayPort cable to connect directly to the monitor.
If I use the HDMI adapter to connect to the monitor everything works fine. I can use closed clamshell with no issues. My assumption is that this is an OS bug. I have tried resetting SMC, NVRAM, and even reinstalled 10.13.1 via Internet Recovery with no luck. I don't believe this is an issue with the cable or the monitor itself since everything works fine when its not in closed clamshell.
Is anyone else experiencing an issue or have any solutions aside from ones I've tried?
MacBook Pro (Retina, 15-inch, Mid 2015), macOS High Sierra (10.13.1)