Recently i decided to do some H files,suddenly taken place an Issue for me …
I created Geo node and in Context level i created Curve node,lines after enter was invisible (just markers visible) …
I changed preferences-3dviewports-scene renderer GL 3.3 to GL 2.1
then problem Solved … 8)
have u any ideas ?!

Try with the latest build Houdini 13.0.575.

There was a Nviida bug fixed.

thanks