diff --git a/include/types/channel.h b/include/types/channel.h
index 88a52a412..8bc395830 100644
--- a/include/types/channel.h
+++ b/include/types/channel.h
@@ -105,7 +105,7 @@
 #define CF_STREAMER       0x00010000  /* the producer is identified as streaming data */
 #define CF_STREAMER_FAST  0x00020000  /* the consumer seems to eat the stream very fast */
 
-/* unused: 0x00040000 */
+#define CF_WROTE_DATA     0x00040000  /* some data were sent from this buffer */
 #define CF_ANA_TIMEOUT    0x00080000  /* the analyser timeout has expired */
 #define CF_READ_ATTACHED  0x00100000  /* the read side is attached for the first time */
 #define CF_KERN_SPLICING  0x00200000  /* kernel splicing desired for this channel */
diff --git a/src/proto_http.c b/src/proto_http.c
index f0dd0c83d..249485085 100644
--- a/src/proto_http.c
+++ b/src/proto_http.c
@@ -4919,8 +4919,8 @@ void http_end_txn_clean_session(struct session *s)
 	s->req->cons->conn_retries = 0;  /* used for logging too */
 	s->req->cons->exp       = TICK_ETERNITY;
 	s->req->cons->flags    &= SI_FL_DONT_WAKE; /* we're in the context of process_session */
-	s->req->flags &= ~(CF_SHUTW|CF_SHUTW_NOW|CF_AUTO_CONNECT|CF_WRITE_ERROR|CF_STREAMER|CF_STREAMER_FAST|CF_NEVER_WAIT|CF_WAKE_CONNECT);
-	s->rep->flags &= ~(CF_SHUTR|CF_SHUTR_NOW|CF_READ_ATTACHED|CF_READ_ERROR|CF_READ_NOEXP|CF_STREAMER|CF_STREAMER_FAST|CF_WRITE_PARTIAL|CF_NEVER_WAIT);
+	s->req->flags &= ~(CF_SHUTW|CF_SHUTW_NOW|CF_AUTO_CONNECT|CF_WRITE_ERROR|CF_STREAMER|CF_STREAMER_FAST|CF_NEVER_WAIT|CF_WAKE_CONNECT|CF_WROTE_DATA);
+	s->rep->flags &= ~(CF_SHUTR|CF_SHUTR_NOW|CF_READ_ATTACHED|CF_READ_ERROR|CF_READ_NOEXP|CF_STREAMER|CF_STREAMER_FAST|CF_WRITE_PARTIAL|CF_NEVER_WAIT|CF_WROTE_DATA);
 	s->flags &= ~(SN_DIRECT|SN_ASSIGNED|SN_ADDR_SET|SN_BE_ASSIGNED|SN_FORCE_PRST|SN_IGNORE_PRST);
 	s->flags &= ~(SN_CURR_SESS|SN_REDIRECTABLE|SN_SRV_REUSED);
 
@@ -5463,7 +5463,7 @@ int http_request_forward_body(struct session *s, struct channel *req, int an_bit
 			 * such as last chunk of data or trailers.
 			 */
 			b_adv(req->buf, msg->next);
-			if (unlikely(!(s->rep->flags & CF_READ_ATTACHED)))
+			if (unlikely(!(s->req->flags & CF_WROTE_DATA)))
 				msg->sov -= msg->next;
 			msg->next = 0;
 
@@ -5515,7 +5515,7 @@ int http_request_forward_body(struct session *s, struct channel *req, int an_bit
  missing_data:
 	/* we may have some pending data starting at req->buf->p */
 	b_adv(req->buf, msg->next);
-	if (unlikely(!(s->rep->flags & CF_READ_ATTACHED)))
+	if (unlikely(!(s->req->flags & CF_WROTE_DATA)))
 		msg->sov -= msg->next + MIN(msg->chunk_len, req->buf->i);
 
 	msg->next = 0;
diff --git a/src/stream_interface.c b/src/stream_interface.c
index 67a5234fa..9f7e979ed 100644
--- a/src/stream_interface.c
+++ b/src/stream_interface.c
@@ -658,7 +658,7 @@ static void si_conn_send(struct connection *conn)
 	if (chn->pipe && conn->xprt->snd_pipe) {
 		ret = conn->xprt->snd_pipe(conn, chn->pipe);
 		if (ret > 0)
-			chn->flags |= CF_WRITE_PARTIAL;
+			chn->flags |= CF_WRITE_PARTIAL | CF_WROTE_DATA;
 
 		if (!chn->pipe->data) {
 			put_pipe(chn->pipe);
@@ -702,7 +702,7 @@ static void si_conn_send(struct connection *conn)
 
 		ret = conn->xprt->snd_buf(conn, chn->buf, send_flag);
 		if (ret > 0) {
-			chn->flags |= CF_WRITE_PARTIAL;
+			chn->flags |= CF_WRITE_PARTIAL | CF_WROTE_DATA;
 
 			if (!chn->buf->o) {
 				/* Always clear both flags once everything has been sent, they're one-shot */