You cannot jump up onto a block from a flowing lava block that has level 3 or lower.

What I expected to happen was....

Holding the jump button and the direction the higher block was in to make the player climb unto it

What actually happened was....

The player would bob up and down and would not be able to get out onto the higher block

Steps to reproduce:

1. Put a lava source block on flat ground
2. Put a block 1 meter away in the direction of the resulted flowing lava that has a level of 3 or lower (so replacing the one with level 2 for 3, 1 for 2 etc)
3. Get into the said flowing lava block
4. Hold the direction the placed higher block is in as to get to the edge of it, like you are trying to climb onto it
5. Hold the jump button to try to climb onto the higher block