RDF message/bug?

So I just recently queued in a RDF for Frost Lord Ahune, upon finding the group it didn't automatically teleport me in, instead I was presented with a message something along the line of "cannot enter while jumping or falling", I was mounted on my Storm Sabre, stationary on the ground outside the AH in Stormwind,
I dismounted & tried to teleport in, same message, tried /reload, same message, left the group & took the 30 minute debuff, exited game, relogged in, no issues entering whilst mounted with Pit of Saron or Occulus before, other than the obvious stated in the message, what triggers this to happen? Or is it just another one of those lovely random Warmane bugs that pops it's head up every now & then ?

I just tried to reproduce it and it seems fine so I'm guessing this is one of those slightly random issues.