Not NOT a bug, but this is the ancient bug where if you log in too close to a mission giver, it will incorrectly appear with missions you should no longer be able to see (or in TSW missions would show as too high a level, even if they weren’t too high for you). Moving a ways a way and back should fix it for now.
Yup, that’s the first mission, (the one with the blue signets reward,) not the repeatable version which is Bounty: More Winter Holidays Champions.
It’s been so long since I had this that I forgot it existed. After 7 years it’s not a bug. It’s a feature.