Bug description
Action: I input identity equip @p minecraft:fox {Type:snow} into a command block.
Expected result: The nearest player should turn into a white fox.
Observed result: No transformation occurs. Command block logs [An unexpec]ted error occurred trying to execute that command.

Miscellaneous

• Using identity equip @p minecraft:fox {Type:snow} in the chat (rather than in the command block) works as expected.
• Attempting identity equip @p minecraft:fox {EntityTags:{Type:snow}} in the command block also does not work.
• The problem is not unique to foxes; parrots, for example, also do not work as expected.

Workaround

• It seems /execute as @p run identity equip @s minecraft:fox {Type:snow} works as a workaround, though I assume this requires the player to have permissions.