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Can you list one or two of the games that are missing so I can investigate why it's not picking these up?
I did add up all the achievements we have logged for you in the database, and it matched your Gamerscore count here (which also matches what Xbox shows), so I'm not exactly sure what could be missing.
Happened to check your profile on TA. I think I found a bug there as it seems to be counting some games that had achievements added later as completions
Says you completed this but there are 25 achievements and 20 are earned. Whether that's the case for all the missing games, not sure... just the first one I found that was missing.