The Bug
Foxes & Wolves don't appear to spawn in the new Grove biome. This is most likely because foxes & wolves can't spawn on Snow or Snow Blocks
Reproduce
Load up a single biome Grove
Do /effect give @e[type=fox] glowing 1000 or /effect give @e[type=wolf] glowing 1000
Fly around and do that command every once and a while
❌ Notice you get no returns
Expected Result
The Wolves & Foxes would spawn in the Grove since in the 21w37a changelog it was stated: "Spawns wolfs, rabbits, and foxes."
I can confirm this issue though rabbits spawn normally there. I've updated your report to be more concise and reflect the information better