I have noticed similar behavior.
SRM - Submitter cancels a Request (Request status = Cancelled by user), but the child ticket, in this case a Work Order, is not updated - it remains Assigned. So while the Submitter thinks they have cancelled their request, the WO Assignee continues with fulfillment. I dont' see any entry in Work Detail or anything to indicate to the WO Assignee to not proceed.
Have you verified that the transition between Rejected and Cancelled is authorized for requester?
Have a look in this form.
If this transition is not allowed, it can explain the issue you met
The REQ shows a status of "Planning" or "Initiated" as seen in Request Details. Workflow has already created and assigned a Work Order. In the REQ details, there is an option to cancel the request. The submitter cancels the REQ which changes the REQ status to "Cancelled (by User)". At no time was the REQ rejected.
I will pursue disabling the "Cancel Request" button - this process feature doesn't make sense. Why would the toolset allow the requestor to think they can cancel a process, but not take any action to halt the downstream steps?
I have the same issue with V8.1 and wonder if anyone every got a work around.
In my specific case the service request creates a change record in the 'Planning in progress' status and when the request is cancelled the change remains in the 'Planning in progress' state and i need to it move to a cancelled state.
Do you have authorized transition from "Planning in progress" state to "Canceled"?
To test it, you can verify if you are able to cancel your change directly from change