Bitcoin's spot price exhibits abnormal trading patterns near Polymarket settlement windows consistent with manipulation, with prices reversing shortly after

"spot-market order flow increased sharply near settlement, and prices frequently reversed soon afterward, behavior the researchers said is consistent with settlement-price manipulation."

"They report sharp increases in Bitcoin spot-market order flow just before settlement, followed by rapid price reversals. order-flow concentrates near the settlement boundary, and spot prices then unwind quickly after resolution—suggesting the pre-settlement movement may not persist beyond the contract's settlement point."