Could it be that you have the following checked: Work Enviroment> User Preferences> On-screen options>Automatic Pen color visibility
When the color of an element, like the wall fill in your example, matches the screen background, the program makes the element color slightly different for ease of viewing. It has no affect on the printed output.
Erika
Architect, Consultant
MacBook Pro Retina, 15-inch Yosemite 2.8 GHz Intel Core i7 16 GB 1600 MHz DDR3
Mac OSX 10.11.1
AC5-18
Onuma System
"Implementing Successful Building Information Modeling"