No worries, not an offensive question.
I don’t take it as offensive but then I barely ever hear it from people who aren’t desi themselves so I’ve never even really had the opportunity to see how it feels from outsiders.
I don’t know of any other meaning for it than to refer to people from the subcontinent.
Maybe it’s like Paki, which while in Pakistan, we used frequently, but there was the furor over Bush using it, and also apparently Brits use it in a very negative way. So…you know, that’s changed. I guess it’s like anything, be careful and don’t use it for people who don’t like it.