Light armor pasive effect BUGed ?

[maara 3]

Hi, i was just checking the  bonuses from set on warlock .... so here is the  problem i found ... if i take down all  equip and dyes  i have cast speed 233 when i equip light armor  my cast speed is 344  what is  bonus cast speed  around 47-48% but on pasive it said : When equiped with light armor, increases Casting speed by 88%.  do i count it from bad stat  or  there is description  bad or  wrong setting on this pasive ?

[San0 2427]

it counts 88% of the char base casting speed stats, excluding anything else that gives cast speed like passive skills, buffs and so on.

so passive skills like fast spell casting or any extra bonus from the WIT stats are not taken in consideration.

[zorgzor 62]

For example robe give 100% casting speed for you, and light give 88% so different of you stats with light will be 12% less than with robe.