In map bm_c1a1b, just after you get the crowbar (I can’t get the console to work, so no coordinates, sorry).
I got this glitch two times. You start with these shelves, one upright, on fallen down:
I moved a chair to try to stand on it to get through the hole in the wall. I bumped it against one of the shelves, and it blipped out of existence. The first time, it happened with the upright one, and later, when I tried to reproduce it, it the sideways one disappeared:
