When I place a sticky piston at y=1 facing upwards or at y=255 facing downwards, it doesn't pull back blocks

How to reproduce:

y=1:
1. Dig to y=1 and place a sticky piston facing upwards
2. Place a block above the sticky piston
3. Power and unpower the sticky piston

y=255
1. Build to y=255
2. Place a block under the piston
3. Power and unpower the sticky piston

(Idk if this is two different bugs, but they were so similar that i put them in one bug report)