IBM BPM instances are in completed state but tasks are Active

Due to a program error there might be a scenario when instance is in completed state but the task is in received state.

there are 3 Ifixes you have to install to get that solved. Below are links to technote for them

https://www-01.ibm.com/support/docview.wss?uid=swg1JR53167

https://www-01.ibm.com/support/docview.wss?uid=swg1JR52533

http://www-01.ibm.com/support/docview.wss?uid=swg1JR57381

EXECUTION_STATUS column in LSW_BPD_INSTNCE table

You need to query the database to get the status of your business process definition (BPD) instances. What is the meaning of the EXECUTION_STATUS field in the LSW_BPD_INSTANCE table?

Flag	Meaning
1	The BPD instance is active.
2	The BPD instance has completed.
3	The BPD instance has failed. Look at the ERROR and ERROR_STACK_TRACE for further details.
4	The BPD instance has terminated.
5	The BPD instance did not start because its message event condition returned false.
6	The BPD instance is suspended,