Hmm interesting ... I personally still struggle to pick out a 'D' sound but in any case, whatever sound it may be, it sounds like a single consonant that joins the two words
I'd said an 'R' and not a 'D' simply since I perceived that sound through my ears to be rather rolling
It seems to me that people coming from different languages hear pronounciations in a new language (sometimes very) differently. This keeps coming up again and again. I find it interesting. If only one could "hear" what the other person is hearing, it would make teaching and learning new languages much easier.