I'm trying to update a user but I'm getting the following error: BadRequestError: bad 'pages' parameter

What I'm doing is the following:

user = intercom.users.find(email="bob@example.com")
user.custom_attributes['firstName'] = 'Bob'
intercom.users.save(user)

Any ideas why this is not working?

UPDATE: I have been able to get this to work with id (intercom's id) and user_id (id assigned by us) but still not with email.