Oh, Google updated their servers, and "body" is not required any more!

ChangeLog

@@ -6,6 +6,8 @@
  - DNS options used to be cleared from DNS queries, with the exception
 of flags and payload sizes. This is not the case any more.
  - Android builds use a newer NDK, and add compatibility with API 19.
+ - DoH queries are smaller, since workarounds are not required any more
+after Google updated their implementation.
 
 * Version 2.0.16
  - On Unix-like systems, the server can run as an unprivileged user,

dnscrypt-proxy/xtransport.go

@@ -268,7 +268,6 @@ func (xTransport *XTransport) DoHQuery(useGet bool, url *url.URL, body []byte, t
 		qs := url.Query()
 		qs.Add("ct", "")
 		encBody := base64.RawURLEncoding.EncodeToString(body)
-		qs.Add("body", encBody)
 		qs.Add("dns", encBody)
 		if padding != nil {
 			qs.Add("random_padding", *padding)