diff --git a/mysql-test/suite/galera/r/MW-336.result b/mysql-test/suite/galera/r/MW-336.result
index 0bf8d9d390982..1b5d2984e3910 100644
--- a/mysql-test/suite/galera/r/MW-336.result
+++ b/mysql-test/suite/galera/r/MW-336.result
@@ -2,39 +2,99 @@ CREATE TABLE t1 (f1 INTEGER) Engine=InnoDB;
 connection node_1;
 SET GLOBAL wsrep_slave_threads = 10;
 SET GLOBAL wsrep_slave_threads = 1;
+SELECT COUNT(*) FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER = 'system user' AND (STATE IS NULL OR STATE NOT LIKE 'InnoDB%');
+COUNT(*)
+11
+SHOW STATUS LIKE 'wsrep_thread_count';
+Variable_name	Value
+wsrep_thread_count	11
 connection node_2;
 INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
 connection node_1;
 SET GLOBAL wsrep_slave_threads = 10;
 SET GLOBAL wsrep_slave_threads = 20;
 SET GLOBAL wsrep_slave_threads = 1;
 connection node_2;
 INSERT INTO t1 VALUES (1);
-INSERT INTO t1 VALUES (2);
-INSERT INTO t1 VALUES (3);
-INSERT INTO t1 VALUES (4);
-INSERT INTO t1 VALUES (5);
-INSERT INTO t1 VALUES (6);
-INSERT INTO t1 VALUES (7);
-INSERT INTO t1 VALUES (8);
-INSERT INTO t1 VALUES (9);
-connection node_1;
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
 SET GLOBAL wsrep_slave_threads = 10;
 SET GLOBAL wsrep_slave_threads = 0;
 Warnings:
 Warning	1292	Truncated incorrect wsrep_slave_threads value: '0'
 connection node_2;
-INSERT INTO t1 VALUES (10);
-INSERT INTO t1 VALUES (11);
-INSERT INTO t1 VALUES (12);
-INSERT INTO t1 VALUES (13);
-INSERT INTO t1 VALUES (14);
-INSERT INTO t1 VALUES (15);
-INSERT INTO t1 VALUES (16);
-INSERT INTO t1 VALUES (17);
-INSERT INTO t1 VALUES (18);
-INSERT INTO t1 VALUES (19);
-INSERT INTO t1 VALUES (20);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
 connection node_1;
 SET GLOBAL wsrep_slave_threads = 1;
+connection node_2;
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+INSERT INTO t1 VALUES (1);
+connection node_1;
 DROP TABLE t1;
diff --git a/mysql-test/suite/galera/t/MW-336.test b/mysql-test/suite/galera/t/MW-336.test
index 8cd363aa019ee..4bdbfb2ecff30 100644
--- a/mysql-test/suite/galera/t/MW-336.test
+++ b/mysql-test/suite/galera/t/MW-336.test
@@ -8,15 +8,28 @@
 CREATE TABLE t1 (f1 INTEGER) Engine=InnoDB;
 
 --connection node_1
+
 SET GLOBAL wsrep_slave_threads = 10;
 SET GLOBAL wsrep_slave_threads = 1;
+
+--let $wait_timeout=600
 --let $wait_condition = SELECT COUNT(*) = 11 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER = 'system user' AND (STATE IS NULL OR STATE NOT LIKE 'InnoDB%');
 --source include/wait_condition.inc
 
+SELECT COUNT(*) FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER = 'system user' AND (STATE IS NULL OR STATE NOT LIKE 'InnoDB%');
+SHOW STATUS LIKE 'wsrep_thread_count';
+
 --connection node_2
-INSERT INTO t1 VALUES (1);
+# Generate 11 replication events
+--let $count = 11
+while ($count)
+{
+  INSERT INTO t1 VALUES (1);
+  --dec $count
+}
 
 --connection node_1
+
 SET GLOBAL wsrep_slave_threads = 10;
 --let $wait_condition = SELECT COUNT(*) = 11 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER = 'system user' AND (STATE IS NULL OR STATE NOT LIKE 'InnoDB%');
 --source include/wait_condition.inc
@@ -28,40 +41,40 @@ SET GLOBAL wsrep_slave_threads = 20;
 SET GLOBAL wsrep_slave_threads = 1;
 
 --connection node_2
-INSERT INTO t1 VALUES (1);
-INSERT INTO t1 VALUES (2);
-INSERT INTO t1 VALUES (3);
-INSERT INTO t1 VALUES (4);
-INSERT INTO t1 VALUES (5);
-INSERT INTO t1 VALUES (6);
-INSERT INTO t1 VALUES (7);
-INSERT INTO t1 VALUES (8);
-INSERT INTO t1 VALUES (9);
-
-
---connection node_1
---let $wait_condition = SELECT COUNT(*) = 12 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER = 'system user' AND (STATE IS NULL OR STATE NOT LIKE 'InnoDB%');
---source include/wait_condition.inc
+# Generate 21 replication events
+--let $count = 21
+while ($count)
+{
+  INSERT INTO t1 VALUES (1);
+  --dec $count
+}
 
 SET GLOBAL wsrep_slave_threads = 10;
 SET GLOBAL wsrep_slave_threads = 0;
 
 --connection node_2
-INSERT INTO t1 VALUES (10);
-INSERT INTO t1 VALUES (11);
-INSERT INTO t1 VALUES (12);
-INSERT INTO t1 VALUES (13);
-INSERT INTO t1 VALUES (14);
-INSERT INTO t1 VALUES (15);
-INSERT INTO t1 VALUES (16);
-INSERT INTO t1 VALUES (17);
-INSERT INTO t1 VALUES (18);
-INSERT INTO t1 VALUES (19);
-INSERT INTO t1 VALUES (20);
+# Generate 21 replication events
+--let $count = 21
+while ($count)
+{
+  INSERT INTO t1 VALUES (1);
+  --dec $count
+}
 
 --connection node_1
 --let $wait_condition = SELECT COUNT(*) = 2 FROM INFORMATION_SCHEMA.PROCESSLIST WHERE USER = 'system user' AND (STATE IS NULL OR STATE NOT LIKE 'InnoDB%');
 --source include/wait_condition.inc
 
 SET GLOBAL wsrep_slave_threads = 1;
+
+--connection node_2
+# Generate 21 replication events
+--let $count = 21
+while ($count)
+{
+  INSERT INTO t1 VALUES (1);
+  --dec $count
+}
+
+--connection node_1
 DROP TABLE t1;
diff --git a/mysql-test/suite/wsrep/t/variables.test b/mysql-test/suite/wsrep/t/variables.test
index 1315f090d5c32..40b869422ff07 100644
--- a/mysql-test/suite/wsrep/t/variables.test
+++ b/mysql-test/suite/wsrep/t/variables.test
@@ -101,8 +101,10 @@ SHOW STATUS LIKE 'wsrep_thread_count';
 --echo # Setting wsrep_cluster_address triggers the creation of
 --echo # applier/rollbacker threads.
 SET GLOBAL wsrep_cluster_address= 'gcomm://';
+
 --echo # Wait for applier threads to get created.
-sleep 3; 
+--let $wait_condition = SELECT VARIABLE_VALUE = 2 FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_thread_count';
+--source include/wait_condition.inc
 
 --replace_regex /.*libgalera_smm.*/libgalera_smm.so/
 SELECT @@global.wsrep_provider;
@@ -113,8 +115,11 @@ SHOW STATUS LIKE 'wsrep_thread_count';
 
 SET @wsrep_slave_threads_saved= @@global.wsrep_slave_threads;
 SET GLOBAL wsrep_slave_threads= 10;
+
 --echo # Wait for applier threads to get created.
-sleep 3; 
+--let $wait_condition = SELECT VARIABLE_VALUE = 11 FROM INFORMATION_SCHEMA.GLOBAL_STATUS WHERE VARIABLE_NAME = 'wsrep_thread_count';
+--source include/wait_condition.inc
+
 SHOW STATUS LIKE 'threads_connected';
 SHOW STATUS LIKE 'wsrep_thread_count';
 
diff --git a/sql/wsrep_var.cc b/sql/wsrep_var.cc
index 7fe120beb8edf..aaae487b2e2c5 100644
--- a/sql/wsrep_var.cc
+++ b/sql/wsrep_var.cc
@@ -594,7 +594,9 @@ void wsrep_node_address_init (const char* value)
 
 static void wsrep_slave_count_change_update ()
 {
-  wsrep_slave_count_change += (wsrep_slave_threads - wsrep_prev_slave_threads);
+  wsrep_slave_count_change = (wsrep_slave_threads - wsrep_prev_slave_threads);
+  WSREP_DEBUG("Change on slave threads: New %lu old %lu difference %lu",
+	  wsrep_slave_threads, wsrep_prev_slave_threads, wsrep_slave_count_change);
   wsrep_prev_slave_threads = wsrep_slave_threads;
 }