Minecarts won't go up on rails or powered rails on height of about 31 blocks above lowest bedrock. I tried on serveral places, it's allways same height.

What I expected to happen was to climb up in minecart

What actually happened was, minecart bounced of nothing and went back down instead of up. It does however work when going from top down to bottom.

Steps to Reproduce:
1. Build a mine and put rails in it, both powered and non powered, start on top of the world and go all the way down.
2. Put minecart on bottom.
3. Try to go upwards. It bounces of nothing on 31 blocks height.