The bug: When standing in a berry bush, you can't jump one block high.
Steps to reproduce:
Place a berry bush and a regular block next to each other.
Walk into the berry bush. (Be careful, it might hurt!)
Try to jump on the block and you'll see it's impossible.
This might be working as intended, but it is quite unclear to me.
The berry bush has a slow effect similar to that of soul sand or cob webs. So you lose all momentum when attempting to jump since you're inside the block. So this isn't a bug.