FAULTY DISPLAY OF ARCS WITH LARGE RADIUS

[SAWMAN56]

USING civil3d 2017

I have roadway construction items drawn; median, drive isles, guardrails, etc.
they are offsets of a centerline construction with a 13000 foot radius.
All of the lines appear normal in model space, but in the layout tab,
they appear broken and offset as if it is in 2 pieces, like the San Andreas Fault.
My display settings are shown in the attached screen shot.
The guardrail in the screen shot is a straight line.
The other lines are large radius curves and do not display properly.
What is causing this paper space viewport fault line ?

[cadtag]

is the scale set in C3D Toolspace Settings tab, Drawing Settings, the same valueas the viewport scale?

and

Are Xref's/ Dref's involved?

[SAWMAN56]

The linework is from an xref base file, Also, the display gets better or worse
when zooming in and out in PAPER SPACE.
viewres and arc smoothness are at maximum