Suggestion:

Check the update frequenzy between the game and the Xbox console companion. My activity feed ain't updated properly in there. Achievements etc. are not there from today's game for example. Now i know it's not something that comes from the Sea of Thieves crew / Rare itself, but might be an idea to check anyway as the Xbox console companion fetches the info from somewhere. Just a thought, not an in-game important one, but still.