2 matches Momentum Control, immediately followed by 1 match Survival. Waited through "scoreboard" every time and didn't select or do anything else until in queue for next match. The game only counted 2 of the matches toward pinnacle. This has been going on for QUITE A WHILE. If it helps (assuming Bungie will put some effort into figuring it out), when a match fails to count it seems to correspond to when I end up in orbit for some reason after the score screen times out (with no interaction from me), rather than in the queue for a subsequent match. PC, Win 10, etc.