Video of The Bug: http://www.youtube.com/watch?v=5PSWtDEHSr0
Description: This bug was heavy annoying in 1.15 seems to be back or still in 1.23 even though sounded like it got fixed. Jumping near players in 1.23 in SMP causes you to only reach a max of 4 blocks or 3 blocks that you can jump onto.