Redundant records are inserted by JPAPlaceholderResolverStrategy

Running com.sample.ProcessJPATest
...
Task1 Entry
A process instance started : pid = 1
john starts a task : taskId = 1
Task1 Exit
Task2 Entry
mary starts a task : taskId = 2
Task2 Exit
java.lang.AssertionError: expected:<1> but was:<8>
	at org.junit.Assert.fail(Assert.java:88)
	at org.junit.Assert.failNotEquals(Assert.java:834)
	at org.junit.Assert.assertEquals(Assert.java:645)
	at org.junit.Assert.assertEquals(Assert.java:631)
	at com.sample.ProcessJPATest.testProcess(ProcessJPATest.java:135)
...

mysql> select * from application;
+----+------+-----------+
| id | type | person_id |
+----+------+-----------+
|  1 | A    |         8 |
+----+------+-----------+
1 row in set (0.00 sec)

mysql> select * from person;
+----+----------+
| id | fullName |
+----+----------+
|  1 | John Doe |
|  2 | John Doe |
|  3 | John Doe |
|  4 | John Doe |
|  5 | John Doe |
|  6 | John Doe |
|  7 | John Doe |
|  8 | John Doe |
+----+----------+
8 rows in set (0.00 sec)