HTTP/2 requests carry the client's host only in the :authority
pseudo-header, with no literal Host header. build_upstream_request
copied headers verbatim, so the upstream request had no Host, and
hyper-util's legacy client (set_host=true default) filled it in from
the upstream URI, sending Host: 127.0.0.1:3000 instead of the client's
host. Backends like Gitea build absolute URLs from that host, causing
the admin self-check mismatch and intermittent wrong asset URLs.
Reconstruct Host from the request URI authority for HTTP/2, preserve
the client's Host header for HTTP/1.1, and let the URI authority win
if both are present.
glm-5.3-flash
203fcadffd