Pen Weight is the issue. Inside AutoCAD MS or PS it appears like a normal line thickness. But when you plot to a plotter or PDF file the thick lines appear or in this case Bone Figures. I like that term.
The window glass (or the line in the middle and on both ends) must have a pen color that is thicker then the wall casing color.
If that is a block easy fix. But make sure there are not two lines on top of each other. The one on top may show a color that you know prints thin but one under may have a thicker printing color. I have always had issues like this when receiving file from MEP AutoCAD.
I am assuming that you are using a CTB plotter setting but does not matter. Only other you must check is does the line have a Thickness assigned to it. Sometimes it may have a color that picks the thickness through the CTB PEN Settings, unless someone assigned a thickness to the individual line itself. Check your properties. A quick fix is also open your block up, draw a line on the correct layer, use your Match Properties tool and select the Bone Lines.
Hope this help!
Thanks, JRR.
