Is Alaska hard to poll because of how small the electorate is?
That and Alaska is a very elastic, independent state. Plus, it's not part of the continental United States, either.
I would take this poll with a grain of salt (only because it's Rassy), but Treadwell is probably only doing better against Begich than Sullivan is because he's already spent most of his money on ads and resources already while Sullivan has barely spent anything, but has lots of cash on hand. So Sullivan is definitely favored still in the primary with his money and conservative support while Begich continues to try and mess this race up and "go solo." It's still a tossup and this seat would likely be 5th to go if Dems do lose that many in November.