India Four Two - at busy times descent may be delayed, used to happen years ago too, usually due to outbound climbing traffic on northerly routes.
Silberfuchs - Are you with, (or were you with), CX by any chance.
Did you contact ATC when you were on the ground and ask what was the cause etc. ? The reason I ask is that CX and QF were the constant complainers about SIA getting perceived preference at Changi but when incidents were investigated it turned out not to be so.