I was playing Portal Stories: Mel and was in the test with the secret Rainbow Core, and i stood on the right-hand button holding the cube.
I tried to get it through the door (Or at least get it jammed in) but accadentally stepped off the button.
The cube was glitched in the door, I jumped at it trying to get it unstuck.
I started flying backwards into the acid... also, i shot a blue portal where the reversed funnel was( I didn't have any other portal formed)
and it turned purple.