Can I top up my Youtrip card with my Standard Chartered unlimited cashback and get the 1.5% cashback?

I've seen similar questions on Seedly and it said that the cashback from SC unlimited doesn't apply to prepaid cards (Youtrip). However, I have a friend who used his SC unlimited cashback card to top up to Youtrip, and he got credited the cashback. It was in the credit card statement. Please help!