implications of a node

[waltertaus]

Hallo,
I am using jBPM in a database environment. I have the following process definition

<?xml version="1.0" encoding="UTF-8"?>
<process-definition xmlns="" name="TestFork">
<start-state name="StartState1219404587924">
<transition to="StartDecision1219404587924/StartDecision1219404587924"></transition>
</start-state>
<super-state name="StartDecision1219404587924">
<decision name="StartDecision1219404587924">
<transition name="To_R9v0MGIXEd2c76EEAkhdWA" to="../Fork1/Fork1">
</transition>
</decision>
</super-state>
<super-state name="Fork1">
<fork name="Fork1">
<transition name="To_1k7IQHAeEd2zyONQHdQlYg" to="../State1/State1">
</transition>
<transition name="To_atT-cGReEd2afZhBo4aBRw" to="../State2/State2">
</transition>
</fork>
<join name="Join1">
<event type="node-enter">
<script><expression>
executionContext.setDiscriminator(true);
</expression></script></event>
<transition name="End" to="../End/End"></transition>
</join>
</super-state>
<super-state name="State1">
<state name="State1">
<transition name="To_QPWKwGReEd2afZhBo4aBRwJoin" to="../Fork1/Join1">
</transition>
</state>
</super-state>
<super-state name="State2">
<state name="State2">
<transition name="To_QPWKwGReEd2afZhBo4aBRwJoin" to="../Fork1/Join1">
</transition>
</state>
</super-state>
<super-state name="End">
<end-state name="End">
</end-state>
</super-state>
</process-definition>

When I run this process past the fork, I correctly have two child tokens, one for State1 and one for State2.

Now I add a node in front of the fork. My process definition now looks as follows.

<?xml version="1.0" encoding="UTF-8"?>
<process-definition xmlns="" name="TestFork">
<start-state name="StartState1219404587924">
<transition to="StartDecision1219404587924/StartDecision1219404587924"></transition>
</start-state>
<super-state name="StartDecision1219404587924">
<decision name="StartDecision1219404587924">
<transition name="To_R9v0MGIXEd2c76EEAkhdWA" to="../Node1/Node1">
</transition>
</decision>
</super-state>
<super-state name="Node1">
<node name="Node1">
<event type="node-enter">
<script><expression>
System.out.println("Node1 entered");
executionContext.leaveNode();
</expression></script></event>
<transition name="To_QPWKwGReEd2afZhBo4aBRw" to="../Fork1/Fork1">
</transition>
</node>
</super-state>
<super-state name="Fork1">
<fork name="Fork1">
<transition name="To_1k7IQHAeEd2zyONQHdQlYg" to="../State1/State1">
</transition>
<transition name="To_atT-cGReEd2afZhBo4aBRw" to="../State2/State2">
</transition>
</fork>
<join name="Join1">
<event type="node-enter">
<script><expression>
executionContext.setDiscriminator(true);
</expression></script></event>
<transition name="End" to="../End/End"></transition>
</join>
</super-state>
<super-state name="State1">
<state name="State1">
<transition name="To_QPWKwGReEd2afZhBo4aBRwJoin" to="../Fork1/Join1">
</transition>
</state>
</super-state>
<super-state name="State2">
<state name="State2">
<transition name="To_QPWKwGReEd2afZhBo4aBRwJoin" to="../Fork1/Join1">
</transition>
</state>
</super-state>
<super-state name="End">
<end-state name="End">
</end-state>
</super-state>
</process-definition>

When I now run this process past the fork, I have four child tokens in JBPM_TOKEN table, two for State1 and two for State2.
Can somebody explain why this happens and how to avoid this behaviour.

Thanks in advance
Walter