diff --git a/sidecar/index.ts b/sidecar/index.ts
index 9d09ecf..f257a5f 100644
--- a/sidecar/index.ts
+++ b/sidecar/index.ts
@@ -307,7 +307,12 @@ const server = Bun.serve({
           // `appSubUrl`, patched below by the same pass, is what makes Gitea's own scripts correct.
           if ((out.get('content-type') ?? '').includes('text/html')) {
             const body = rewriteHtml(await upstream.text(), base, origins);
+            // BOTH of these, and the second is not optional. `.text()` has already decompressed, so the
+            // body being returned is plain — while `out` still carries Gitea's `content-encoding: gzip`.
+            // The next hop believes that header, tries to gunzip plain text, and fails with ZlibError:
+            // a 502 that names nothing and looks exactly like the sidecar being unreachable.
             out.delete('content-length'); // the body just changed length
+            out.delete('content-encoding'); // and is no longer compressed
             return new Response(body, { status: upstream.status, headers: out });
           }
         }