The untamed versions still appear in all their colour variants in the wild, but after taming it seems they'll always appear in the colour you originally tamed.
So either taming now tracks skin as well as NPC id, or someone has gone to the trouble of giving unique IDs to every colour. That is possible.
I first noticed this with the Crystal Spine Basilisk a couple of patches back. I've now confirmed:
- Sand-Husk Scarab
- Rabid Hyena
- Oasis Crocolisk (couldn't find grey-with-green-fins variant, I wonder if it was removed)
- Enthralled Crustacean
- Crystal Spine Basilisk
- Vale Howler (couldn't find grey-with-black-face variant, maybe removed?)
- Venomtip Needler
- Curious Jungle Monkey
- Zulian Gnasher
- Baradin Fox
- Pyreshell Scuttler (they seem to have removed all the water, I initially fell to my death from my seahorse trying to reach them!)
- Marsh Crocolisk
- Borer Beetle (confirmed by GormanGhaste)
- Dredge Worm (confirmed by GormanGhaste)
In all cases I tested every colour and resummoned ~6-10 times per colour.
I haven't yet confirmed five NPCs: Savage Worg (UK), Jeweled Scarab (HoO, summoned in the Earthrager Ptah fight. Beware there are two NPCs with this name and the one in the previous corridor already isn't a colour-changer), Spiny Raptor (Lost Isles, so goblin starting zone only), Mountain Mastiff (worgen starting phase of Gilneas only), Wary Mastiff (Gilneas, but possibly starting zone only, not sure). Gilnean Hound is still listed on Petopia as a colour-changer but all of them are actually grey now.
Could others please confirm this so I can be certain it's not just some weird caching thing with my client making it look like they're always the same)? If possible in the presence of others so you can be sure they all see the same thing.
I'd also be interested in people confirming it if they already had a colour-changer tamed from prior to the beta and brought it across with them. I wonder how that would be handled.
I should add that the basilisk is the only one I've tested over an extended period, i.e. over many days.
If this fix remains then it means that some people who love their pets changing colour will be unhappy. But it also means that some colours will become stable for the first time (like the Pyreshell Scuttlers). I think it's ultimately a great fix.