I agree, after trying to turn off the linework of both a stair and ramp and the attached railings above the cut-line I still see some linework. In the case of a stair I still see the inside railing sketch-line and in the case of the ramp some of its boundary and railing lines as well did not turn off.
Send it into Revit On-line Help as an issue.
Mel Persin, AIA
AEC Technology Consultant
Technology to Visualize and Realize Solutions
MasterGraphics, Inc.
mel.persin@masterg.com