I'm starting to think this might be a bug. I have a portalable panel in my level with a light bridge directed at it, and an info_placement_helper on it to make sure that any portal placed on it has the light bridge on the bottom edge.

The info placement helper works fine if your shot at the panel is unobstructed - however, if you fire at the panel through the light bridge it doesn't take effect. Is this a known issue? Is it possible to fix this somehow by setting up a portal trigger and automatically spawning the portals on the panel?

Light bridges are creating at their endpoints helpers automatically. If you want to put your own helper point there, you have to disable the bridges own in it's keyvales (standard YES).

Thanks! That's exactly what it was.