Entity's despawning and AFK lag

1. Entity's that aren't supposed to despawn (such as hopper in a minecart) have been despawning. I'm not sure if dyed sheep are supposed to despawn but they have too.
2. When I go AFK for a while to benifit from my farms or wait for villager to lower prices the game will sort of lag, going into a state where I can't open chests, mine or break blocks, or interact with the game in general apart from movement