altium negativ view
The plane layers in Altium Designer are negative layers. That means that objects which can be seen on those layers are voids in the copper. You aren't seeing "outlines", you're seeing the places where the copper is going to be removed.
Likewise with direct connections to the plane from thru-hole vias and pads. You won't see anything where they connect to the plane, because there is no copper to be removed. Only the pads and vias that pass thru the plane without connecting are going to show anti-pads.
Board fabricators know about negative planes. It's the normal way of showing a plane layer, and it keeps the Gerber files smaller and simpler than positive plane layers.