South Korea’s largest centralized crypto exchange Upbit, which has more than $1 billion in daily trading volume, resumed trading of the Aptos token early Monday after briefly suspending deposits and withdrawals of APT without warning after it detected an “abnormal deposit attempt.”

The disruption seems to have occurred when Upbit’s automatic wallet system incorrectly read code and labeled scam token ClaimAPTGift as the same as the legitimate APT tokens, according to Twitter user Definalist.  The exchange made the discovery while monitoring APT movement on and off the platform, according to a statement.

The disruption comes in a post-FTX collapse world where some crypto users have grown more skeptical of centralized exchanges, although Upbit was recently thriving. Its July trading volume rose a whopping 42% in July, reaching nearly $30 billion, behind only Binance.

Upbit warned of potential price disruption from the pause, asking users to “pay special attention to price differences with other exchanges that occurred during the “suspension” of Aptos deposits and withdrawals,” in a statement.

APT was recently trading at $5.59, up more than 5% over the past 24 hours. The token has a total market cap of $1.3 billion with about $324 million in daily trading volume, according to CoinMarketCap data.