I noticed it about a week ago irl. Saplings I planted were not growing. I then thought it may have been their proximity to other objects. After adjusting in game, I also noticed that the grass and crops were also not regenerating. So I thought I just needed to wait longer (i.e days in-game) with no success. Attached is a picture of my game after a full 5 days in game, and after all the fixes below

Fixes tried: 

In-game update.

Restart game.

Removed texture pack.

Reinstalled base game, beta, and pack.

Unsubscribed from beta, reinstalled, re-subscribe to beta, reinstalled texture pack.