ActiveJob worker always returning 301 to jobs from SQS queue

Question

I have active-elastic-job setup on an Elastic Beanstalk worker with Puma/Ruby 2.4. This is receiving jobs from SQS however it's always returning 301 to every job. The jobs are created on an Elastic Beanstalk web environment with Puma/Ruby 2.4 and it has the same secret key.

When I create the job from the web environment I can see the job being received by the SQS daemon on the worker environment:

2018-11-15T01:37:14Z message: sent to http://localhost:80/
2018-11-15T01:37:14Z http-err: 35232854-1f0c-4dcc-b97f-6708e3b07b81 (206) 301 - 0.003

I can also see the request hitting nginx :

127.0.0.1 - - [15/Nov/2018:01:37:14 +0000] "POST / HTTP/1.1" 301 217 "-" "aws-sqsd/2.4" "-"

However there is nothing in the puma log.

In the app it has config.force_ssl = false

Here's the middleware :

use Rack::Sendfile
use HerokuDeflater::ServeZippedAssets
use Rack::Deflater
use HerokuDeflater::SkipBinary
use ActionDispatch::Static
use ActionDispatch::Executor
use ActiveSupport::Cache::Strategy::LocalCache::Middleware
use Rack::Runtime
use Rack::MethodOverride
use ActionDispatch::RequestId
use ActionDispatch::RemoteIp
use Rails::Rack::Logger
use ActionDispatch::ShowExceptions
use ActionDispatch::DebugExceptions
use Airbrake::Rack::Middleware
use ActionDispatch::Callbacks
use ActionDispatch::Cookies
use ActionDispatch::Session::CookieStore
use ActionDispatch::Flash
use ActionDispatch::ContentSecurityPolicy::Middleware
use Rack::Head
use Rack::ConditionalGet
use Rack::ETag
use Rack::TempfileReaper
use Warden::Manager
use ActiveElasticJob::Rack::SqsMessageConsumer
run Operator::Application.routes

Since there's nothing in the puma log, it seems it's hitting some middleware that's returning the 301? Any ideas where I should look?