Japanese cryptocurrency exchange Zaif has admitted a “system glitch” allowed customers to temporarily ‘buy’ trillions of dollars worth of Bitcoin for free last week, local online journal The Asahi Shimbun reported Wednesday, Feb. 21.

Zaif informed users about the glitch in a post on their site Tuesday, Jan. 20, explaining that for 18 minutes on Feb. 16 users accidentally found themselves able to ‘trade’ yen for virtual currency  — at an exchange rate of 0 yen per coin.

Asahi Shimbun reports that seven users were able to obtain crypto for “free”, but the exchange managed to cancel all illicitly-gained transactions.

Asahi Shimbun reports that one “buyer” made an attempt to sell 2,200 trillion yen (about $20 trillion) in Bitcoin before the problem was resolved.

Zaif’s Twitter posts reveal further criticism from users, who complain about poor backend performance and lack of support.

The latest difficulties comes as Zaif gains increased regulatory scrutiny in the wake of January’s $530mln hack of Japanese crypto exchange Coincheck.

Despite the security lapse, Japan’s licensing system for exchanges has seen considerable popularity since an legal overhaul of the space in April 2017.

Licensed members will even form part of an umbrella self-regulatory group from April this year, with details still to be ironed out, Cointelegraph recently reported.

Meanwhile, technical errors on mainstream consumer interfaces are far from unheard of. In January, 2018 online retailer Overstock revealed a glitch that resulted in customers being able to choose between Bitcoin and Bitcoin Cash as payment options, with the price figure remaining the same.