Blizzard has changed how Class Trials work, preventing them from looting some specific rare mounts. Previously, class trials were used to check several different realms for rare mounts, often to share or speed up the camping process, which is no longer possible for some.
The following mounts cannot be looted on trial characters:
- Time-Lost Proto Drake
The following mounts can be looted on trial characters:
- Draenor Rares such as Poundfist and Pathrunner
- Grey Riding Camel
- Garrison Bosses
- Long Forgotten Hippogryph
https://www.wowhead.com/item=121815/voidtalon-of-the-dark-star is yet to be confirmed as being lootable or not by Class Trial Characters.
Thanks to Cougarlee from the Secret Finding Discord for reporting on this find. Make sure to join their discord and check the #mounts channel for more updates on this hidden change.