The tournament had largely been seen as a success until the final day, when bettors were only able to place a wager on two NFL play-off games.
When the first of the two matches overran, several players could not bet on the second game in time, having their entire bankroll in play during the first.
Consequently, a civil complaint has been filed by participant Christopher Leong in a New Jersey court, alleging "negligent, arbitrary and capricious operation" of the contest by DraftKings.
Rival operator FanDuel has been quick to report the issue on its website The Duel.
Although the company specified the author is not a FanDuel employee, whose views do not necessarily reflect those of the firm, the article is clearly available on one of its feature B2C sites and advertises FanDuel’s sportsbook at the bottom of the page.
The article includes the following lines: "It turns out that not every sports bettor is willing to just roll over and accept being screwed out of a shot at $1m.
"Though this development is just a civil complaint, this likely won't be the last we hear of this debacle, especially with more states filing to legalise sports gambling each and every month."