I have this problem with LayOut, I try to create other scenes and save them in separate files, the strangest thing is that I have two other details on the same page that does not have that problem, they were rendered correctly to hybrid.
Does your computer have integrated Intel graphics as well as the Radeon card? If so, have you checked to see which one SketchUp and LayOut are actually using? In SketchUp you can see that by going to Window>Preferences>OpenGL.
If it is the Radeon card that is being used, you might try updating the card’s drivers.
When you installed SketchUp 2018 Pro, how did you do it? Did you just double click on the downloaded installer file to launch it or did you right click on the installer and select Run as administrator?
I think since you don’t remember how it was installed, I would be inclined to do a repair installation anyway. Log in to your computer as you normally do with SketchUp and LayOut closed. Find the installer exe and right click on it. Choose Run as administrator (this is not the same as logging in as administrator) and then, when presented with options, choose Repair.