It's not a bug, it's a feature! Jokes aside, this is a pretty hilarious visual bug. My best guess is that the client thinks the dog is sitting, whilst the server knows the dog is standing but has failed to communicate that, similar to blockglitching (1.8) and sprinting sneaking players.
It's not a bug, it's a feature! Jokes aside, this is a pretty hilarious visual bug. My best guess is that the client thinks the dog is sitting, whilst the server knows the dog is standing but has failed to communicate that, similar to blockglitching (1.8) and sprinting sneaking players.