Curve piping

I’m using curve piping in an interior model to simulate stitching.

The curve piping is applied to a dashed line. Things worked fine up to recently. Now the curve piping does not show, although it was enabled. Also the dashed line for the stitching doesn’t show anymore, it’s become just a continuous line, however, in the properties, the line is still a dashed line.

When I copy paste the lines out of the file into a new one, all is well.

Anything to do with the side of the original file?

(Memory is around 34%)

Hello - see if LineTypeDisplay is set to display linetypes…