EDIT: Title should be "Not Posting Achievements Unlocked on iOS"
I was searching Xbox in App Store and came across Snap Attack. Installed it and unlocked 5 of the 10 achievements. While GTN scanners picked up the game and the achievements page shows as unlocked, those achievements do not appear on my blog singly or as a group. I'm assuming the data is pulled slightly different from Xbox.com or is this an issue?
Like Fsh said, they're not timestamped. They won't show up in your feed because there's no date related to them. They also won't be included in your weekly/yearly totals, like anything done offline (as far as I know).