The answer why miles don't post some times has two answers.

1. The partner airlines don't care enough to track down the problems and correct them. I have one AF route that only post manually. I have to go to the CTO every time I fly and request credit.

2. DL just does not care enough to put pressure on the partners to force them to fix the problems.

Back in days gone by, SN, Swiss Air and Austrian posted within 24 hours for any flight I ever took. There was a real synergy between the alliance parterns, unlike now.