Sorry, just reporting what I see. I’m pretty sure ‘localhost’ there is wrong too. My web dev is mostly ancient, it’s been over a decade since I’ve worked with stuff professionally. Getting as far as I did took some time, Docker & Ruby & such are all fairly new to me. tcpdump, on the other hand… I know that tool. 
I still think sending ‘localhost’ to a remote server, in any situation, is the wrong behavior, though.