Hidden edges not shown

Hi,

what might be possible reason(s) for hidden edges not being shown in the drawing, after having already selected 'Show Hidden Edges' in the right-clicked popup menu? (see attached for sequence)  The hidden edge (orange line) belongs to edge of an object on the interior of the duct.

This is just one of all the lines belonging to a subassembly object that can't show with the hidden edges option.

attempts I have made so far to troubleshoot but to no avail:

i) restart solidworks

ii delete and undo object

iii) clicked on rebuild icon at top

iv) clicked items in the subassembly and 'show hidden edges' one by one instead of highlighting all together to do it together

v) switch display style and undo (don't want to show everything else with hidden lines so don't wnat to use this option)

I appreciate any suggestions anyone can offer.

Thanks,

CC

(see attached)

SolidworksDrawings And Detailing