I am experiencing the same issue. Apple is so good about fixing these types of things. I hope it gets cleared up soon. I need to switch between mirror and external display to get mine working after a sleep. UGGGGHHHH!!!! APPLE HELP!!!!

I am also having this same problem. Is anyone using OnScreen App from LG? I found this app was causing kernel panic. I start the Mac, start the OnScreen, get my monitors working, then shut off OnScreen app. Is anyone else doing this? BTW - there is a new version of OnScreen Control available today - 5.23. I am waiting to see if it causes a crash.

following up on my post to this thread - I found a thread out there in the inter webs that was similar to this one. There was an answer posted that recommended adjusting the main display (native) to 50 Hz (down from 60 Hz) to see if it helped. Indeed it worked for me. I do not have the link to the article, but this change in the main laptop Mac display setting allowed the 2 external LG monitors to be recognized and display without crashing my system. I hope this helps others.