Intro from 1993 so it was probably written on ECS, but if we assume that on OCS configuration is a bug emulation then I checked and it appears since version WinUAE 3.0.0.
On WinUAE 2.6.1, 2.7.0., 2.8.0, 2.8.1 this intro works perfectly on OCS configuration.
I personally don't consider such cases as bugs, if on any configuration demos run perfectly
