The price of bitcoin slumped again today after Bitfinex closed its order book, citing issues with its post-trade processing.

The Hong Kong-based exchange, which witnessed a ‘flash crash‘ just last week, halted trading for a seven-hour period this morning. The Bitfinex price promptly fell a further 3.8% when it reopened at 12:31pm UTC.

In a statement on Reddit, Zane Tackett, Bitfinex’s director of community and product development, said:

“Earlier today, at 5:27 UTC, we encountered an issue with post-trade processing, upon which we decided to halt trading to ensure consistency in the order book.”

Users were given a 15-minute window to cancel their orders before trading restarted. Many expressed frustration with the beta service, which has been plagued by technical glitches that Bitfinex’s Phil Potter attributed to its transition to AlphaPoint software.

According to Bitcoinity data, the exchange handled 22,400 trades today, down from 81,500 this time last week. Since the flash crash, it has been shunted to the fourth most popular exchange, succeeded by Huobi and BTC China.

Last week’s flash crash at Bitfinex saw the CoinDesk Bitcoin Price Index fall 14% to a four-month low of $214.03. At press time, it remains $30 below pre-flash crash levels.

Besides Bitfinex, a bitcoin market maker told CoinDesk the slump could also be due to the uncertainty around Bitcoin XT – the contentious client aiming to ‘fork’ bitcoin. He said: