Hi!
If Diagonal Jump is set to false on my plugin parameters, and it still is able to jump, probably is because of the Visustella plugins. I disabled it here and it works properly. Now, Visu plugins abre obfuscated, so I can't just take a look at their code to see what is going on.
What I will do is try to find a better way on my plugin to prevent the diagonal jumping when the diagonal parameter is false. I will also add a new parameter to, in case diagonal jump is allowed, to let the plugin reduce in -1 tile the distance when jumping diagonally, so the character does not jump too far when using diagonal. I will let you know when I have fixed it