Paladin's Threaten

I've noticed that paladin's threaten doesn't work on bosses.
Is this a bug or is it a MapleSaga thing?
Need a reply asap!

 

I think it has never worked on bosses Not a bug, just the way it should be

 

most of the skills are not effective against bosses, examples to be: threaten ( you mentioned), Seal (mage), poison mist (mage), venom star/stab (nightlord/shadower), dispel (bishop).