diff --git a/server/modules/protocol/mysql_backend.c b/server/modules/protocol/mysql_backend.c
index 0cb80a059..fc11484c7 100644
--- a/server/modules/protocol/mysql_backend.c
+++ b/server/modules/protocol/mysql_backend.c
@@ -299,13 +299,17 @@ static int gw_read_backend_event(DCB *dcb) {
                                                 dcb->delayq,
                                                 gwbuf_length(dcb->delayq));
                                 }
-                                rsession = session->router_session;
-                                ss_dassert(rsession != NULL);
-                                /*<
+                                ss_dassert(session->state == SESSION_READY);
+                                /**
                                  * vraa : errorHandle
-                                 * rsession should never be NULL here.
-                                 **/
-                                ss_dassert(rsession != NULL);
+                                 * rsession may be NULL if session is being created
+                                 * in parallel by another thread.
+                                 */
+                                while(session->router_session == NULL)
+                                {
+                                        usleep(1);
+                                }
+                                rsession = session->router_session;
 
                                 LOGIF(LD, (skygw_log_write_flush(
                                         LOGFILE_DEBUG,
@@ -792,12 +796,18 @@ static int backend_write_delayqueue(DCB *dcb)
 
         if (rc == 0) {
                 /*< vraa : errorHandle */
+                /**
+                 * This error can be muted because it is often due
+                 * unexpected dcb state which means that concurrent thread
+                 * already wrote the queue and closed dcb.
+                 */
+#if 0
                 LOGIF(LE, (skygw_log_write_flush(
                         LOGFILE_ERROR,
                         "%lu [backend_write_delayqueue] Some error occurred in "
                         "backend.",
                         pthread_self())));
-                
+#endif           
                 mysql_send_custom_error(
                         dcb->session->client,
                         1,
diff --git a/server/modules/protocol/mysql_common.c b/server/modules/protocol/mysql_common.c
index a48ec8ed8..1ee25db27 100644
--- a/server/modules/protocol/mysql_common.c
+++ b/server/modules/protocol/mysql_common.c
@@ -362,7 +362,7 @@ int gw_receive_backend_auth(
         {
                 ss_dassert(n < 0 && head == NULL);
                 rc = -1;
-                LOGIF(LD, (skygw_log_write(
+                LOGIF(LD, (skygw_log_write_flush(
                         LOGFILE_DEBUG,
                         "%lu [gw_receive_backend_auth] Reading from backend dcb %p "
                         "fd %d in state %s failed. n %d, head %p, len %d",