Thanks for checking out this issue with polymorphic associations.
This is tiny Rails 6.0 app, and the relevant code is in app/models and in db/migrations.
To see the problem for yourself and play around with it, clone this repo, bundle install, start the Rails console and run:
Organization.create(name: 'org')
User.create(name: 'user')
User.first.organizations # SQL looks fine
Organization.first.users # SQL has access_to_type condition twice