Task Trigger Action does not work

Task Trigger Action does not work

Hi 
before upgrading to 14.3, we added a custom trigger action that executes a script when a task schedule is changed. and it works in the service catalog Flow.
After Upgrading, it seems this functionality no longer works. the Task custom trigger action will not be invoked under any type of action  :( 
Can anybody help me to solve this problem?

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