Try unlinking and relinking your Ubisoft Connect, that seemed to fix my tracker the next time I picked up one of the required collectibles for that achievement

Update: Unlinking and relinking my Ubisoft Connect fixed some but not all of my tracking issues

Try unlinking and relinking your Ubisoft Connect, that seemed to fix my tracker the next time I picked up one of the required collectibles for that achievement

Xbox achievements aren't tracking as they should be. There are many reports on Trueachievements.com that some achievements aren't unlocking at all when requirements are fully met