it has been in the game for years, when walking/jumping on blocks such as trapdoors, scaffolding, anvils, and probably more they make the incorrect sound:

*when jumping/waling on scaffolding and trapdoors they make the sound of the block beneath them and not the correct sound of the trapdoor or scaffolding

*when jumping/walking on an anvil it makes no sound whatsoever 

there is no way to prove this as i know but i can assure this is a game bug as it has been in forever and is not fixed when restarting minecraft