There was no governance attack. This was just extreme negligence from both @Polymarket and @UMAprotocol.
What actually happened was:
1. A user submitted a Yes proposal for "Ukraine agrees to Trump mineral deal before April?" (polymarket.com/event/ukraine-…) and this proposal was disputed, initiating the standard UMA vote process (1 day commit period, 1 day reveal period, market resolves to the winner if the consensus threshold is reached).
2. AFTER every voter had committed, 2 minutes before the end of the commit period (11:58 PM UTC on Sunday), Polymarket issued a clarification stating it was too early for the market to resolve and it wasn't a Yes yet.
3. UMA whales proceeded to reveal Yes in spite of the clarification to avoid being slashed for an incorrect vote, even though they could have coordinated to abstain from voting and roll the vote.
4. Yes won the vote and the market resolved against Polymarket's own clarification. Up until the last few minutes, people thought Polymarket might still call the emergency pause function. Polymarket did issue another clarification 2 minutes before the end of the reveal period (11:58 PM UTC on Monday) -- only to say that the market would in fact just resolve in line with UMA's vote.
There is no "tycoon" who "manipulated the oracle". The voters that decided this outcome are the same UMA whales who vote in every dispute, who (1) are largely affiliated with/on the UMA team and (2) do not trade on Polymarket, and they just chose to ignore the clarification to get their rewards and avoid being slashed.
I personally think Polymarket is far more at fault here for their last-minute clarification because they should have either clarified much earlier into the commit period or not at all, and there's no real explanation for why they didn't clarify earlier except for them just being understaffed and inattentive on the weekend.
@Polymarket @UMAprotocol fwiw I still put most of the blame for this situation on Polymarket and UMA, but @Domahhhh's thread covers important context about how the Yes proposal was specifically timed to capitalize on anticipated negligence: