400 Bad Request behind HAProxy

I use HAProxy to frontend a bunch of dev servers, with SNI, as I have a single IP I can use. This worked fine on 1.5.1, but I just upgraded to 1.5.5, and now my locally hosted appwrite is responding with Bad Request errors. I'm pretty sure it's expecting a header that HAProxy is not sending, but I'm sending all the RFC7239 headers I can think of, and it's still not working. I can't seem to find the backend logs, even in dev mode, that would show me why I'm getting this error. Any suggestions?

does browsing directly to appwrite work?

Yes

What exactly is the full response body you're getting through ha proxy? You're not seeing anything in the docker logs for the appwrite container?

Nothing of note in any of the docker logs

I don't see any requests. Was hoping to find the equivalent of an nginx log or something