In 4.13, the line trace debug only seems to render in the right eye. It’s not rendered at all in the left eye. Hardware used is the Vive.
I’m getting even more bizarre behavior. It draws fine in the left eye, but has crazy HMD-orientation-affected positioning in the right eye, moving in all sorts of wrong directions.
Turn off “instanced stereo” in the project setting and things will return to normal. This, however, appears to be a bug that should be addressed (or maybe someone with more knowledge can offer a better solution that doesn’t require losing the benefit of instanced stereo.