I've noticed the following.

If I do:

user = User.first.all
user.extend Role
user.is_a? Role

returns true as expected.

If I have an objected that is Embedded in the User class like:

def User
   embeds_one :profile
end
def Profile
  embedded_in :user
end

and I do the following:

profile = User.all.first.profile
profile.user.extend Role
profile.user.is_a? Role

it returns false.

I've been struggling to understand why, and I'm wondering whether mongoid is producing this strange behaviour?