Patch 4.0.1(2010-10-12): Bash no longer interrupts non-player spellcasting and now stuns the target for 4 sec, up from 2 sec.
Patch 3.2.0(2009-08-04): Tooltip now specifies that the Interrupt effect only occurs on non-player targets.
Hotfix (2009-06-08):When immune to the stun of following abilities, [Maim], Bash, and [Hammer of Justice] will no longer cause player spells to be interrupted but they will still interrupt NPCs. Also, when these abilities do stun a player target, they will not perform an interrupt effect and lock out the affected magic school. As an example, if a Mage is channeling Arcane Missiles and is hit by Hammer of Justice, Blink will now be available as the Arcane school will not be locked out as it was before.
Patch 3.0.3(2008-11-04): The interrupt from this ability will now work on targets who are immune to the stun.
Patch 0.7(2004-06-15): Rage cost reduced if Bash fails.