Non-existant brushes showing up ingame

Not sure what’s up with it, but I have a brush that I never made showing up in my game. SS:

In Hammer:

Ingame:

I had same broblem but i go it solved you maybe have compling error

do check your compile log.

if nothing referencing it comes up, check for problems with alt + p in hammer

if nothing again, then high light the area in the 2d view, probably top down and select all brushes in that general area and see if an invisible brush comes up. if no, add me on steam.

looks like a messed up brush face, maybe improperly deleted or moved?

make sure the brush isn’t concave at all. clip it if you need to.
otherwise best i can advise is just rebuilding that single area

[editline]13th October 2016[/editline]

saw the top of the walls have the orange texture instead of the grey one, not sure if you changed that or not
also try Vertex Editing the points of the slanted wall onto the edge of the other wall
for some cases its okay to have brushes inside one another but i have no clue how well hammer’s compiler handles brushes on the same plane

finally just press U to unhide all in hammer, maybe you accidentally pressed H somewhere and hid the brush