Originally Posted by
Worldtraveler727
I have had a ton of problems with this, but 99% of them have to do with using some sort of credit from last year or some sort of re-issue/exchange. The agents were telling me that when the system is applying the ticket value, it is doing it against when Delta collected the fare. So for unused tickets I have from 2017, the MQD fairy is trying to apply the value to my 2017 MQD values.
I've had the same issue when I've changed a ticket after booking to a higher fare; when my miles first post it's based on the original, lower fare. Interestingly, I have not had that issue when I change a ticket to a lower fare...