create_or_find_byが動かないケース

test.rb

# create_table :users do |t|
#   t.integer :uuid, null: false
#   t.index :uuid, unique: true
# end
class User < ApplicationRecord; end

User.transaction do 
  User.find_by(uuid: 1) #=> nil

  # ここで別transactionにて
  # User.create!(uuid: 1)

  User.create_or_find_by!(uuid: 1) #=> ActiveRecord::RecordNotFound
end