I saw what initiated this on X a day or so ago. Basically, people were talking about Casey's chances via Polymarket being low, and someone made a retweet that there was only like $120 or so towards Casey, and if any singular person bought in, it could potentially massively influence the needle, and be a huge payout if he won. So it seems like several people bought into him, which tanked Vivek and boosted Casey.
Wouldn't read anything into it right now, but, as many have stated here and on X, Vivek has a habit of putting his foot in his mouth, and has already pissed off most of the electorate who knows about him. And Amy is not well liked either due to her COVID shenanigans. So it's not completely out there that we see a Governor Putsch. Though if he gets a lot of traction the GOP might slide Tressel in to either replace Vivek, or divide Casey's voting bloc in the primary.