Various animals, wolves, mudcrabs, bears etc don't seem to play the block sounds associated when using a shield. Blocking with a weapon on it's own plays the correct sound however. I decided to focus on mudcrabs and check out if perhaps the impact data was not set up correctly. they use FXMeleeClawMedium (0001f272) and it doesn't look like anything was wrong with it. Out of curiosity, I made an unplayable copy of the unarmed weapon (000001f4) and assigned it FXMeleeClawMedium in the impact data section and then added it to EncMudcrabGiant. When I spawned it to test, it played the shield block sound as intended. I have no idea why exactly this is happening, and adding separate unarmed weapons for each impact data type for every creature seems a huge pain and potentially a compatibility pain, so I'm hoping this at least provides a start to a more creative solution.