I just downloaded the new November build (#1904627) and opened my City project in it. First time i started the editor some buildings and trees were all red. Here is a pic:
So i closed the editor, it asked if i want to save i chose no.
I ran the editor again and when i opened the same map it were all green like this:
This time instead of quitting i Played in Editor and in-game some buildings were pink. (Sorry i forgot to take a screenshot of it). When i played again everything was back to normal but still everything renders green inside the editor.
Ok so i deleted the DerivedDataCache and the configs and restarted the editor and now the editor renders normally. But when i play this is the result:
1294-
I closed the editor again and started up to see that red color again. Not sure what might be the issue. Right now it is unusable. 
Do you have baked lights or is it all dynamic? Also, when i first opened the latest map i’d been working on i got an error about some material and Rocket crashed, but then it worked just fine after i let it compile all of the materials in the content browser.
I finally figured out what the issue was. Its Global Illumination.
@Mehmet: Its all dynamic. No baked lights.
With GI:
Without GI:
So i disabled GI in PostProcess and now everything is back to normal. YAY! 
