Some entities remain grayed out or in a certain color on display in modelspace.

This is cacan be solved by using MAPDISPLAYMANAGER command Then choosing STYLIZATION , set to OFF. Colors on entities should display once more.

From an AUGI discussion post https://forums.augi.com/showthread.php?171267-LAYER-AND-MODEL-SPACE-COLORS-NOT-SHOWING-PROPERLY

This really stumped be for a bit in civil 3D, glad someone in AUGI ran into the same problem.