This is not a bug. It is plainly recorded in the text files.
It may be odd, but that is the way it is.
Use feral rage when mana burned. Better yet, use fury on right click and feral rage on left click...keep the feral ball up, and use it more when things take your mana.
edit, reversed left vs right but you can always go the other way around.
[ Post edited by Kramuti ]
"The only difference between genius and stupidity is that genius has its limits" Einstein