Getting Unable to release order base ship unit... because the ship unit would be over released Error

We are trying to release Order Base ship units through scheduler:

The Process followed is as : -

There are total of 3 order base ship units.

One order base ship unit is received on Order base creation and it is released.

On order base update we are getting additional 2 order base ship units which we intend to release using scheduler —> we are trying to release 2 Order Base ship units which are not yet release after inserting a release instruction with IS_PROCESSED as 'N' and IS_AUTO_RELEASE as 'Y' and then Release Unprocessed Release Instruction from Order base ship unit agent using public data type association ORDER BASE SHIP UNIT TO ORDER BASE.