Mongoid 7.0 create instance with has_many validation issue

To whom it may concern, 

We have models like this:

class User

  has_many :clients

end

class Client

  has_and_belongs_to_many :tasks, counter_cache: true

end

And the issue is

user = User.create

user.clients.create(attributes)

Raising Error:

TypeError: no implicit conversion of Symbol into Integer

It was from here enumerable .
Because when creating contact I am not passing any task attributes.  At the same time counter_cache is trying to count tasks which is nil for this case.

It was working correctly for mongoid 6.4. 

Your fast reply is very appreciated as we are counting on version 7 to improve our server side performance. Many thanks!