Stun status doesn't last long enough?

[Advancechao]

I have been playing on my warlock a lot recently and I noticed that stun never ever lasts 5 seconds. I tried it on an earth ghost and it usually lasts anywhere between 1 - 2 seconds instead. Is there a way to make someone be stunned longer, like a certain trick?

I sometimes notice that just stunning the opponent without using any skills immediately afterwards may make them get stunned longer.

[shbly12]

I guess not, but I'm not sure.
I think that, the more was the stunning skill's level, the more the chance and the more the stunning time.
It's random, one day I made a Devil Horse get stunned for 4 seconds

[Swindler]

when you attack it dissapears ,-

[Advancechao]

when you attack it dissapears ,-

But when glaivers use soul spear, the stun lasts the whole five seconds and they can keep attacking while they enemy is in stun. I've noticed the problem on rogues as well (screw hits them and the stun disappears half a second later).