diff --git a/addons/promex/service-prometheus.c b/addons/promex/service-prometheus.c
index 5158d3233..06eb1eea9 100644
--- a/addons/promex/service-prometheus.c
+++ b/addons/promex/service-prometheus.c
@@ -1511,6 +1511,8 @@ static void promex_appctx_handle_io(struct appctx *appctx)
 		case PROMEX_ST_DONE:
 			/* no more data are expected. Don't add TLR because mux-h1 will take care of it */
 			res_htx->flags |= HTX_FL_EOM;
+			si->cs->flags |= CS_FL_EOI;
+			res->flags |= CF_EOI;
 			appctx->st0 = PROMEX_ST_END;
 			/* fall through */