Here are some things to try if Outlook isn't properly syncing or updating contact groups:

1. Check that Outlook is up-to-date; if not, update Outlook.
2. Make sure syncing is enabled and create sync partnerships between Outlook and other contacts sources.
3. Manually update Outlook contacts.
4. Check Outlook and accounts settings for any misconfigurtations.
5. Make sure contact groups are up-to-date with any new contacts added or deleted.
6. Try to reset the Outlook cache.
7. If all else fails, try to reinstall Outlook.