https://www.gamespot.com/articles/ps4-demo-for-yakuza-6-pulled-because-the-full-game/1100-6457004/

Update 2: Sega has now confirmed that it did indeed pull the demo because players were able to access more than intended. "We apologize, but have had to remove the Yakuza 6: The Song of Life demo from the PlayStation Store," it said on Twitter. "We are as upset as you are, and had hoped to have this demo available for everyone today. We discovered that some were able to use the demo to unlock the full game. We're looking into the nature of the issue. Thank you for your patience."

Update: The Yakuza 6 demo has now been pulled from the PlayStation Store, at least in the US. The unusually large size of the demo is apparently due to the fact that the entire game is included, though only the prologue should be accessible. However, players have reportedly found a way to access more--possibly the entire game. We have not been able to verify this as of yet, but the demo is indeed gone from PSN for the time being. We've reached out to Sega and will report back with anything more we learn. The original story follows.