For certain bookings, Expedia does not forward the cancellation to the channel manager (myallocator). This article explains the cause and also the solution for it.
If a booking is a Hotel Collect booking and the booking was canceled by the property in the Expedia extranet -> Expedia does not forward us the cancellation notification.
"At this time there is no intent to change this in our system. The expectation is that since the hotel is to collect the payment and they initiate the cancellation that they should be aware that the booking has been canceled. This is true no matter the connection type"
If you canceled a Hotel Collect booking directly in Expedia's extranet, you must also cancel the booking within myallocator (or your PMS) to update the system with the cancelation.