Battle Fatigue

Anyone have any information on this? I've been looking around but to no avail, as far as I know this fatigue forces experience gain to lessen however i cannot find where it tells you if your current class is "fatigued" could someone please go in depth on this? thank you.

Your current SP numbers will turn orange, and you will receive a message saying "You gain bonus SP" along that lines, but it really isnt bonus anything, your get less SP. that is the fatiuge. The message just hasnt been changed...