Minecraft wiki entry for Hoe, associated text: Tilling a dirt block that has a dirt block on top of it changes it to farmland even though it cannot be used. If a hoe is used on a block horizontally adjacent to such a block, the first block reverts to dirt and the selected block is not tilled.
When a hoe breaks, it does not display the tool breaking animation like on other tools, because tilling is not predicted client-side.
The textures for the post 1.14 iron and stone hoes have an error, where color for the edge of the handle is partly the same color as the edge of the top part. This isn't present in any other tool.