On 28 June, players were able to bet on Korean baseball league (BOO) and Chinese Professional Baseball League matches after incorrect start times were posted, due to a manual entry error.

It is thought the MGM Resorts-operated casino has posted the largest sportsbook loss in Las Vegas history, after an event has started.

An ESPN report stated there were approximately 50 questionable wagers placed on self-serve kiosks at the Bellagio between 1:30am and 3am PST, with one winner securing $137,000 on a $250 10-leg parlay.

However, the matches in South Korea and China actually began at 1am and 2am, but the BetMGM software posted the incorrect start times. The four KBO matches involved began at 1am and ended just before 4am.

According to ESPN, a Twitter user posted an image of an eight-leg parlay involving KBO games which all began at 1am, with the ticket having a time stamp of just before 3am, and that $100 ticket won $11,156.60.

The Nevada Gaming Control Board is investigating the matter, to decide whether the wagers should be considered valid or not. The Control Board is required to be notified when there is a dispute of more than $500.

BetMGM operator Roar Digital said in a statement it had identified and addressed a trading error and was now working with the Nevada gaming authorities on the matter.