Can you try signing out of Bungie.net and then signing in again (using your Microsoft Account as usual). There is a step in the sign in process where we pick up your Gamertag from Microsoft. Our current hypothesis is that this step occasionally fails and your gamertag does not get linked. Since we no longer make you sign in everyday, you are not getting as many chances to get your gamertag linked again. Signing out and signing back in will force another attempt to pickup your gamertag. It may take about 15 minutes to see a result after you sign in. Let me know if it helps.