It appears that the Deepstar Aurelid does not gain its ground movement speed increase in areas where you cannot fly like Oribos or Zereth Mortis. I can understand this as possibly intended (“at home in the water as much as the air” but maybe not the ground)? But if so, it should not be a valid mount when using the favorite mount button.
It works fine in areas where flying is enabled, like going around Orgrimmar.
I noticed this as well. I submitted a bug report. It doesn’t seem like this behavior would be intended. No other mount in the game behaves this way. This mount seems to be stuck at 50% ground movement speed in areas you can’t fly in.
Same here, getting swim speed in no-flying zones as well while normal ground/flight speed in flying zones. Definitely seems unintended.
I was wondering about this myself. I was super jazzed to take my new slimy boi out for questing with my friends and they left me in the dust due to the slow movement speed 
Yup, just got Deepstar Aurelid and addons say it’s only moving at 110% movement speed compared to all other mounts at 210% in zones without flying unlocked.
Same thing happens here - slow ground speed in oribos and other ground mount only places.
It seems to swim at 134% vs 60% normal swim speed. It swims at the same speed as the Poseidus mount in most water. So it behaves like most swimming mounts. It runs in non-flying zones (Oribos, Maw, Korthia, ZM) at 110% and in flying zones at 220%. So half normal mount speed in non-flying zones
Yep! Just got mine and was so excited, really hope this is just a bug blizz.
Can confirm that the bug is still happening and can provide screenshots. The screenshots are to show it flying around acting normal in orgrimmar but not working correctly in zereth mortis. The swim speed bug is also in oribos.
Essentially anywhere where flight isn’t possible the mount only increases swim speed and does not scale properly.
Same issue here
Surprised this hasn’t been fixed yet considering we’ve already had at least 1 addition patch post 9.2.
ikr? I can use it on my alts with no issue but the 1 zone I wanna use it in that it comes from… nope.
Same issue here, multiple other thread about it and comments on wowhead too. Hopefully it gets hotfixed in tonights fixes!
I’d love to see a fix for this. It’s a wonderful mount!
Really hoping this gets fixed! Especially after fishing for 5 hours for it, and being unable to swim in the entire zone 
Would like to also add that it appears the mount does not accept any mount equipment. It would be a shame to use this mount and be susceptible to daze effects.
Adding a ‘me too’ to this thread as well. If this is intended behavior for the mount, that is truly so sucky.
There’s a twisted irony in a swim speed mount dropping from a zone with no swimmable water.
me too blizzard, spending multiple hours this is not fun to have mount speed bug or intentionally
I am having the same issue. Definitely does not seem like this is how it was intended. I did read that Blizz developers are aware and don’t yet know how to resolve. What if on Tuesday’s update they just erase it from everyone’s account who got it, fix it, then mail it back to everyone?
It’s a known issue! https://us.battle.net/support/en/article/306193
I didn’t know this page existed. Thanks to the Twitter CS who helped me find out!