I recently filed a missing miles claim for a one way trip (BGR-LGA-YUL) booked in paid first (Z). I was awarded a grand total of zero miles. It seemed odd, but I didn’t have the energy to follow up (I generally don’t bank my Skyteam miles with DL) so I did a retro claim with KE and was immediately awarded 125% of miles flown. Not sure if this was a one-off as I’m not at all familiar with Delta’s program, but wanted to share my experience.