This is how I created it:
I had two garbages on my first floor. I clicked on one, then went to the second floor. I came back to my first floor and saw the second one. I clicked on the second one, and before I let the janitor pick it up, I clicked on a slot machine and played a few rounds. When I left the slot machine the "Oops" error appeared.
I cleared the "Oops" error, and took the first screenshot.
I then left the casino and re-entered. The garbage was still there (in a different location) and I clicked for the janitor to clean it. The "Oops" error appeared when the janitor reached the garbage.