Issue
Material of the graphic(s)... will be ignored in render, because it is overriden by materials of graphic faces..." message appears for 3D boolean objects in Quality or Draft Redsdk Render modes:

1-Draw 2 intersecting Spheres with Simple Brick material.
2-Apply 3D boolean add operation on spheres
3-Go to View,Visual Styles and apply quality rendering on it.
4-"Material of the graphic(s) "Brick\Simple Brick" will be ignored in render, because it is overriden by materials of graphic faces..." message appeared.
5-Video attached.

Reason:
As Designed.

Face's material takes precedence over the object's material. If all faces have material, then the material of the object is ignored. This is reported in the message.

Please discussion on forum:
http://forums.turbocad.com/index.php?topic=12782.0
https://forums.turbocad.com/index.php?topic=22058.0

Manual:
(Transfer material from operand on its facet) 
http://doc.imsidesign.com/articles/#!turbocad-2018-user-guide-publication/advanced-preferences-1/