I’ve had this frustrating issue for a while, and it seems to have gotten worse recently.
Sometimes when I have the edge of a surface that is coincident with another surface, I can only snap to it from one side. For example if I have a floor with a wall sitting on the floor, I can’t snap to the bottom edge of the wall—I have to clip into the wall and select the edge from inside the solid volume of the wall.
This doesn’t seem to be an issue of the edge actually not being coincident with the other surface. I’ve had similar behaviors when I use a surface to trim another surface—the new edge can only be grabbed from one side.
The below image is an example. I can’t snap to the highlighted edge from outside of the volume it’s up against. Anyone else have this issue? Hopefully I’ve done a good enough job of describing it…