Improve Shield Block Talent is not giving extra blocks!!

Improve Shield Block Talent is not giving extra blocks!!

Current situation:
When a warrior partially blocks an attack with shield block up, BOTH charges are consumed instead of just one, making this talent useless for end game raiding.

Expected situation:
The correct way the talent functions is as follows: 1/3 gives 1 extra block and increases duration by 0.5 seconds, 2/3 gives 1 extra block and increases duration by 1 second, 3/3 gives 1 extra block and increases duration by 2 seconds.

Improved Shield Block is supposed to allow you to block an additional attack taking it up to a total of 2 blocks, instead of just 1.

Currently, with the Improved Shield Block talent. Both stacks are consumed on damage after activation, only works when you do a full block. Partial blocks cancels out both charges of Improved Shield Block.