Noticed that ashes and the dark phoenix are both missing their signature particle trails when flying using skyriding. The trails are there when you’re on the ground but go away when you lift off.
Seems to be working normally in standard flying mode, but bugged with skyriding.
Update Edit: Posted below that many other mounts lose their effects when skyriding, too. Isn’t just the flaming chickens. 
Been that way in beta for at least a month. Not sure it’s a bug.
Confirmed this just now, myself. It’s bugged, but for some reason, only when using Dragon Riding version of flying. It still works correctly with regular flying
To add to this, it seems than MANY mounts that have particle effects lose them when they take off while skyriding.
A few quick examples are :
the Original Netherdrakes (the wing trails as well as the body glow both turn off)
Cindermane Charger (the fire effects on its hooves, mane and tail all turn off)
Frostwyrms (blue/white chest glow turns off)
Rocket mounts (x53, x51 and x51 x-treme) all lose the smoke trail their engines put out.
Gravewing mounts lose their small wing trails.
Oddly enough, though, not ALL mounts lose their effects in flight.
Invincible keeps its blue/white chest glow.
Smoldering Ember Wyrm keeps its chest flames.
The Grotto Netherwing Drake keeps its body glow (I know it was a dragonriding mount anyway).
It doesn’t seem to be that the effects wouldn’t work if turned on, since some mounts keep them anyway while skyriding. Definitely seems like a bug, though only a mildly annoying one.
Edit: Felsteel Annilator has its boot jets always turned on, even while on the ground and with old style flight mode enabled.
Funny enough, the Lightforged Warframe works fine in old style flight but in skyriding mode it’s boot jets don’t turn on when flying.
The flying mount Felsteel Annihilator is NOT closing the cockpit around/over the player char when flying in Skyriding (unlike it always did in steady flight)
When just walking, even with Skyriding on, it does close the cockpit
So, I suppose it is a bug 
Also, the green sparks from the exhaust on the back of the mount seem to be dimished 
So, Ashes seems to be fixed, but there are a TON of bugs on other mounts…
Please give the other mounts bugs some attention, Blizzzzzz
I can second that Ashes of Al’ar has been fixed but the Dark phoenix hasn’t