There is nothing to resolve. The cmdlet is working as designed.
The cmdlet uses already filters the work item types to ones that can have migrated content. So, all the customer has to do if they don’t want to see 0s is something like what is listed below. What this does is only shows results that have mail counts. They can change this to filter on just about any property in the objects returned by get-mnemigrationresult.
$result | Select totalmailcount,errorcount | Where-Object {$_.totalmailcount -ne 0}
This simply keeps the return from showing those tasks in the migration where there was no data moved etc, for example we have an operation called "PAB_PASS2" which is just one of our migration tasks that runs during a migration. Since that operation runs it is included in that list, since nothing is moved and there are no errors to report, it shows up as that 0 0 return.