Resque and resque-scheduler bug on production environment

gistfile1.rb

require 'resque/tasks'
require 'resque_scheduler/tasks'

task "resque:setup" => :environment do
  Resque.before_fork = Proc.new { ActiveRecord::Base.establish_connection }
end

namespace :resque do
  task :setup do
  # ...
  end
end

Resque error description

PG::Error: ERROR: prepared statement "a3" already exists : 

SELECT COUNT(*) FROM pg_class c LEFT JOIN pg_namespace n ON n.on = c.rel namespace WHERE c.relkind in ('v','r') AND c.relname = $1 AND n.nsp name = ANY (current_schema(false))