The exception was reintroduced: while maintaining polymorphic association

In my Rails 4.2.7 , ruby 2.3.3 application, when I save a certain polymorphic association while keeping the nested form, it gives the stack level too high and rails_admin becomes unresponsive. And when I save the Rails console it gives the following error: fatal: Re-entry exception .

2.3.3 :001 > Post.last.links
  Post Load (10.3ms)  SELECT  "posts".* FROM "posts"  ORDER BY "posts"."id" DESC LIMIT 1
  Link Load (0.8ms)  SELECT "links".* FROM "links" WHERE "links"."linked_item_id" = $1 AND "links"."linked_item_type" = $2  [["linked_item_id", 112], ["linked_item_type", "Post"]]
 => #<ActiveRecord::Associations::CollectionProxy []>
2.3.3 :002 > Post.last.links.create(name: 'see details', link: 'http://www.google.com/')
  Post Load (3.7ms)  SELECT  "posts".* FROM "posts"  ORDER BY "posts"."id" DESC LIMIT 1
   (1.2ms)  BEGIN
  SQL (4.1ms)  INSERT INTO "links" ("name", "link", "linked_item_id", "linked_item_type", "target", "created_at", "updated_at") VALUES ($1, $2, $3, $4, $5, $6, $7) RETURNING "id"  [["name", "see details"], ["link", "http://www.google.com/"], ["linked_item_id", 112], ["linked_item_type", "Post"], ["target", "_blank"], ["created_at", "2017-04-11 15:34:25.320118"], ["updated_at", "2017-04-11 15:34:25.320118"]]
   (0.3ms)  ROLLBACK
fatal: exception reentered
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/abstract/transaction.rb:187:in `rescue in within_new_transaction'
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/abstract/transaction.rb:201:in `within_new_transaction'
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/activerecord-4.2.7.1/lib/active_record/connection_adapters/abstract/database_statements.rb:213:in `transaction'
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/activerecord-4.2.7.1/lib/active_record/transactions.rb:220:in `transaction'
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/activerecord-4.2.7.1/lib/active_record/associations/collection_association.rb:182:in `transaction'
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/activerecord-4.2.7.1/lib/active_record/associations/collection_association.rb:492:in `_create_record'
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/activerecord-4.2.7.1/lib/active_record/associations/has_many_association.rb:187:in `_create_record'
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/activerecord-4.2.7.1/lib/active_record/associations/collection_association.rb:153:in `create'
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/activerecord-4.2.7.1/lib/active_record/associations/collection_proxy.rb:290:in `create'
    from (irb):2
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/railties-4.2.7.1/lib/rails/commands/console.rb:110:in `start'
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/railties-4.2.7.1/lib/rails/commands/console.rb:9:in `start'
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/railties-4.2.7.1/lib/rails/commands/commands_tasks.rb:68:in `console'
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/railties-4.2.7.1/lib/rails/commands/commands_tasks.rb:39:in `run_command!'
    from /Users/starwar/.rvm/gems/ruby-2.3.3@rails420/gems/railties-4.2.7.1/lib/rails/commands.rb:17:in `<top (required)>'
    from bin/rails:4:in `require'
    from bin/rails:4:in `<main>'

      

        
        
        
      

    

Here is an important part of my posting model

class Post < ActiveRecord::Base
  has_many :links, -> { order(created_at: :asc) }, as: :linked_item, dependent: :destroy
  accepts_nested_attributes_for :links, allow_destroy: true

      

        
        
        
      

    

And my link model

class Link < ActiveRecord::Base
  extend Enumerize
  enumerize :target, in: [:_blank, :_self, :_top, :_parent], default: :_blank
  # Associations
  belongs_to :linked_item, polymorphic: true, touch: true

  # Validations

  validates_presence_of :link
  validates_presence_of :name
  validates :link, :url => { allow_nil: false }

  # Scopes
  scope :sorted, -> { order(created_at: :asc) }
end

      

        
        
        
      

    

This exact code is deploying to Heroku and it works great, but it doesn't work on my local machine. And when the rails server stops responding, I have to kill the process and it says

[NOTE]
You may have encountered a bug in the Ruby interpreter or extension libraries.
Bug reports are welcome.
For details: http://www.ruby-lang.org/bugreport.html

      

        
        
        
      

    

And suddenly my tests pass, but I can't add anything via the Rails console or rails_admin panel to a model that has a polymorphic association filling out a nested form.

Thank,