There has been an issue since launch of Ubisoft Connect where achievements do not give out a notification when they are unlocked in game. Many have complained about this issue on the old Ubisoft Forums but the only responses from Ubisoft support were "Our team is looking into the issue" with no further information found here https://forums.ubisoft.com/showthread.php/2287084-Achievements-do-not-appear-after-upgrading-to-Ubisoft-Connect/page15: (https://forums.ubisoft.com/showthread.php/2287084-Achievements-do-not-appear-after-upgrading-to-Ubisoft-Connect/page15)

Please fix this bug.

@ubi-milky

Well... that sure is something. No point in using a launcher that proceeds to take steps backwards and has almost no communication with its own support staff or customers.
Disappointing as always Ubisoft.