When playing with the auto jump selection on, the auto jump triggers when on flat ground while near walls.  As an example, when branch mining at lower levels I typically mine a one wide two tall tunnel until I am satisfied I have gone far enough out.  Sometimes I run into gravel or a cave and the third high "roof" block or higher is mined out or missing ( the ones over the character's head).  When this occurs I have found difficulties on the return trip down the newly created tunnel.  When i hit the stretches of the tunnel that have the missing "roof"  the character auto jumps and i typically face plant into the next "roof" block ultimately slowing down my game play and irritating me.  

Additionally, when swimming while auto jump is activated, when attempting to move forward in water the character bobs as it is trying to auto jump in open water.  In order to dive or swiftly swim I must first sink until the air monitor comes on then swim forward.  This has been extremely problematic when trying to cross water or dive for shipwrecks and such.

My best guess is it has to do with the auto jump registering the blocks to the left and right or the front left and front right of the character.  If the auto jump senses a wall block or water block it tries to jump.  Please feel free to contact me if you need anymore information to understand my view of the problem.

Thank you and keep great work.

Respectfully,

Jeb Bair