Flew LAX-PVG-DEL on MU. My China Eastern ticket showed the fare class as I and J.

Am DL Platinum and was using the trip for all the extra MQMs I'd get.

I called Delta to link the to my ATL-LAX segment. All flight showed up in my Delta app with the fare classes as above.

Fast forward a week... Both are denied all mileage DL credit due to partner denying credit. I call and tweet Delta and they reque it and I get credit... Except my PVG-DEL is only credited as I class even though listed as J. They said the route code is coded as an I class.

Any one ever had that happen? Was using this and a couple future MU flights to bump up to DL diamond... But these "bump downs" are going to make me miss that.

Any suggestions or thoughts?