When I uncheck the checkbox and try to submit the form this is the error that I encounter:
An error happened while submitting the task form : Cannot submit task form a33a34e4-7009-11ec-9bcd-e470b873e0f6: Unknown property used in expression: ${approved}. Cause: Cannot resolve identifier ‘approved’
This is the project link: GitHub - camunda/camunda-get-started-quickstart
Clearly the variables are identified and upon executing the remaining cases I get my desired output on eclipse IDE.
I am using camunda-bpm-run-7.16.0
and camunda-modeler-4.11.1

Issue Resolved you have to first save the form then proceed on completing it only in this way your flow gets executed normally.