That was the first time in history that the bourse halted derivatives trading. In an incident report, the bourse said the root cause related to a specific order generation processing logic for the combination order of Two-Sided Price Quote, namely Combination MO37. Combination MO37 enables two-sided price quotes (that is, both a buy and a sell instruction in the same message) against a combination of futures contracts with different expiry months. The problematic software logic caused some of the orders generated by Combination MO37 to be inserted into the order book twice. Nevertheless, the order generation function of Combination MO37 will continue to be suppressed to eliminate any potential risk.

Source: The Standard December 28, 2020 12:04 UTC