Polkadot, the token for the smart contract blockchain of the same name, rose by more than 70% in just four hours on U.S.-based crypto exchange Coinbase. However, the price on other exchanges followed the larger market sell-off.The crypto market has experienced a massive sell-off since Monday as bitcoin, the No. 1 cryptocurrency by market cap, plummeted below $30,000 during early trading hours Tuesday in the U.S., for the first time since January. DOT’s price, along with most of the major alternative cryptocurrencies, also declined, sinking as low as $13.04 in the past 24 hours, according to CoinDesk 20 data.However, DOT’s price was one of the biggest winners of the day on Coinbase; it went as high as $22.80 around 12:00 p.m. ET Tuesday, up more than 70% in four hours, according to data from TradingView and Coinbase.A spokesperson from Coinbase told CoinDesk the team is currently investigating what happened, and said the price discrepancy of DOT between Coinbase and other major exchanges is likely due to the “send and receive” function being disabled as part of “the incident.”Subscribe to , The San Francisco-based crypto exchange also moved the DOT/USD and DOT/BTC trading pairs on its professional platform Coinbase Pro into limited-only mode at 1:35 p.m. ET as a result of the incident.DOT/USD and DOT/BTC “were moved to limit only to dampen (sic) expected volatility as the asset price reverts to parity with other exchanges once the incident is resolved,” the spokesperson said.There was an incident regarding DOT trading on Coinbase on June 20, but according to both the website and the spokesperson, a fix was implemented on June 21. The U.S. crypto exchange giant started offering DOT trades on June 16.At press time, DOT is changing hands at $15.17 on Coinbase, consistent with its price showing on CoinDesk 20.