The world in a singleplayer game works like it's a lagging server

Generaly "game is laggy" reports are no longer accepted, you'll have to provide a more detailed source of the lag (what causes the game to slow down).

This report is invalid as performance decreases are expected to happen between versions of the game (especially snapshots). Unless a specific performance problem is stated along with the cause of it, the bug tracker cannot provide you with assistance.