It's a glitch that occurs on most non-1.4.4 servers I've played. Some barb skills were updated after a certain point in PW's lifespan.
Bestial Rage added the magic absorb if activated lower than 50% hp
Mighty Swing and Flesh Ream added 100% accuracy
And Alacrity added the chance to freeze.
(there may be more, but that's just what I can think up off the top of my head)
Many servers use the updated skill descriptions without having the actual updated skills.
