CanCanCan, How to store current_ability in memcached

Question

After upgrading CanCan 1.4 to CanCanCan 2.0, I can not anymore cache current_ability into memcached with Dalli.

I got error below :

Cache write: profils/11-20170821121414000000::ability
Marshalling error for key 'development:profils/11-20170821121414000000::ability': can't dump hash with default proc
You are trying to cache a Ruby object which cannot be serialized to memcached.
/usr/local/rvm/gems/ruby-2.4.0@rails5.1.1/gems/dalli-2.7.6/lib/dalli/server.rb:414:in `dump'

I store current_ability in memcached through Dalli by overriding CanCan.Ability::current_ability in app/controllers/application_controller.rb

 def current_ability
     Rails.cache.fetch("#{current_user.profil.cache_key}::ability") do
       super
     end
 end

Why I store current_ability in cache ?

cancan slowing down page loads, Because I have a lot of custom actions in many controllers, each page reload all abilities...

Any pointers in regards to cacheing / optimizing / best practices would be most appreciated. Thanks!

update 1

Add app/models/ability.rb

class Ability
   include CanCan::Ability

   def initialize(user)
     alias_action :edit, :to => :read
     role = user.profil

     if role.label == 'administrateur'
       can :manage, :all
     else
       role.rights.each do |right|
         model = right.resource.constantize rescue nil
         next unless model
         [:read, :create, :update, :destroy].each do |capability|
           can capability, model if right.send("#{capability}?")
         end
       end
       # Custom actions
       can([:collective, :collective_week, :presence, :day_details, :day_details_json], Movement) if can?(:read, Movement)
       can(:quick_add, Movement) if can?(:create, Movement)
       can([:actions, :set_action, :choose, :previous, :families_addresses, :ios,:families_members,:potential_relationships,:list_families,:list_decisions], Person) if can?(:read, Person)
       can(:addresses, Family) if can?(:read, Family)
       ...
       ...
       ...
     end
   end
end

Update 2

Print an object of Ability (below is just a snippet of ability but the stucture is the same) That's the data that I try to store in memcached :

#<Ability:0x000000093030a0
 @aliased_actions={:read=>[:index, :show, :edit], :create=>[:new], :update=>[:edit]},
 @expanded_actions=
  {[:index, :show, :edit]=>[:index, :show, :edit]},
 @rules=
  [#<CanCan::Rule:0x00000008fb3e18
    @actions=[:read],
    @base_behavior=true,
    @block=nil,
    @conditions={},
    @match_all=false,
    @subjects=[AcceptanceReason(id: integer, label: string, created_at: datetime, updated_at: datetime, institution_position: integer, acceptance_number: integer, department_type_id: integer)]>,
   #<CanCan::Rule:0x00000008fb3760
    @actions=[:create],
    @base_behavior=true,
    @block=nil,
    @conditions={},
    @match_all=false,
    @subjects=[AcceptanceReason(id: integer, label: string, created_at: datetime, updated_at: datetime, institution_position: integer, acceptance_number: integer, department_type_id: integer)]>],
 @rules_index=
  {AcceptanceReason(id: integer, label: string, created_at: datetime, updated_at: datetime, institution_position: integer, acceptance_number: integer, department_type_id: integer)=>[0, 1, 2, 3],
   Activity(id: integer, created_at: datetime, updated_at: datetime, institution_id: integer, label: string, activity_type_id: integer, employee_id: integer, department_id: integer, group_id: integer, beginning_at: date, ending_at: date, location: text, comments: text, objectif: text, evaluation: text, colour: string, collective_intervention_mean_id: integer, collective_intervention_status_id: integer, archive: boolean, activity_beginning_time: time, activity_ending_time: time, moyens_materiels: text, transports: text, autres_intervenants: text, budget: text, frequency: string)=>
    [4, 5, 6, 7, 645],
   ActivityCode(id: integer, label: string, created_at: datetime, updated_at: datetime)=>[8, 9, 10]}