If a player obtains a spawn egg with an overridden minecraft:<farm_animal>/variant component then interacts with this spawn egg on a differently-varianted farm animal, the resultant baby farm animal will briefly appear with the parent's variant before correcting itself to the spawn egg's variant.

Steps to reproduce

1. Visit a cold biome
2. Spawn a cold chicken using a chicken spawn egg
3. Obtain an overriding spawn egg with the following command: /give @s chicken_spawn_egg[chicken/variant=warm]
4. Use the obtained chicken spawn egg on the cold chicken
5. Observe that the chicken appears cold, then quickly updates to be warm

These reproduction steps also work for pigs and cows. Note that the flash is very brief and may not even be visible for lower frame rates.