Can confirm that I had the same experience of different buses on my last trip 11 days ago.
Data points below for reference .
Arrived at DXB on EK515 ticketed in J(777-300 ER) on 5th June from DEL. Was dreading the long trek to A concourse from a C or it could even have been D !!!!remote stand just after midnight.
(I was connecting to EK 11 DXB - LGW which is a A380 @0245 and therefore was reasonably sure that it was A concourse but can vary at last minute from my expericence. Due to some error the gates for connecting flights were not displayed on my arrival flight )
As soon as I deplaned, there was a groundcrew member holding a sign directing pax to a differnt buses depending on the connecting flight .
I did ask the crew member and he said that going in that bus will get me directly to the concourse.
A quick look at the signboard looked as if they were all for possible A380 flights / A concourse.
(MAN/LHR/LGW) from memory.
Though I hate remote stands, this did ease the pain a bit.