How to set TaskDecorator in HumanTaskActivityBehavior

Hello

I’m trying to do some custom processing for camunda’s HumanTask and for that I have registered HumanTaskTransformListener to my processEngine and overriden transformHumanTask method - which calls my custom HumanTaskActivityBehavior class for additional task activityBehavior.

But camunda call fails while creating the task , as taskDecorator coming as null -
taskDecorator.decorate(task, this) - here is error trace -

! java.lang.NullPointerException: null
org.camunda.bpm.engine.impl.cmmn.execution.CmmnExecution.createTask(CmmnExecution.java:149)

Any solution to set this TaskDectorator in HumanTaskActivityBehavior from transformHumanTask method?