Imagine you have 2 documents

class User
      embeds_one :pet, validate: false
end

class Pet
    embedded_in :user
end

It should be OK if you want to save user with invalid pet (because of validate: false).

But it seems validate: false option doesn't work as expected, and you'll get validation error when you wan't to store user with invalid pet!

My Mongoid version is 4.0.2