Landing on the top of a stair block at an angle will stop you moving off it

I was able to replicate the bug reliably under the following conditions:

• Stair block is placed upright
• A block is placed behind it to be level with the top
• Stand ~1 block behind the stair and jump onto the spot where the top half starts
• You can move forward until the border of the stair block is reached, and no further.
• Moving backwards will cancel out the bug and you can move normally over the stair again