Curve invisible?

Hi Can anyone please explain this ? (See video)

With History ON, I have made a patch surface, using two curves and a point.
When generating the Patch, the inner curve disappears.
I can still select it from the layers, but as soon I deselect it it disappears again.

when selected, and turning on control points, the curve disappears again.

When nudging one control point, the curve is now visible, and appears stable visible now.

what is going on ?

Thanks

Patch test curve invisible.3dm (3.7 MB)

not sure without a file, maybe post it that somebody can have a look and say more certain what is going on. at first glance it seems there might be some object display mode in play. since the patch surface seems somehow ghosted or rendered or whatnot maybe that obstructs the curve then from being visible. or the curve itself was set to that mode either and in that display mode curves are not shown for instance which would explain it being invisible.

go to wireframe mode select all objects and run SetDisplayMode without selecting anything it will set it to wire and maybe becomes visible. otherwise post that file.

sorry, file is now attached

Ghost mode, 80% transparency
You can see through the surface to see the C-plane, so that curve should be visible.

Maybe its a bug related to History command?

I quit Rhino, and opened this file again, and now the issue is not there anymore.
weird…