ToME: the Tales of Maj'Eyal

i've been using that skill since i got it on a skirmisher. yet it doesn't apply additionnal effects like tooltip says. i'm using insidious and numbing poison so target should get a poison and slow debuff yet nothing happens.
https://imgur.com/a/uvPyn
https://imgur.com/a/BoYLn
Can you fix it plz

log concerning one of those venomous strike

[LOG] Jojo uses Venomous Strike.
[ARCHERY ACQUIRE TARGETS WITH] Hare-Skin Sling Bregerin nil nil
[SHOOT] speed 0.8 => 800
[ARCHERY SHOOT] Jojo 4929 using weapon: Hare-Skin Sling ammo: Bregerin offweapon: nil pf_weapon: nil
[ARCHERY SHOOT dofire] Shooting weapon: Hare-Skin Sling to: 30 20
Adding entity 40531 after 4929
[ATTACK ARCHERY] 40531 to Norgos, the Guardian :: 52.396205878187 3 3 :: 1.640908153701
checkHit 58 vs 16 => chance to hit 100
[ATTACK ARCHERY] raw dam 52.396205878187 versus 3 with APR 3
[ATTACK ARCHERY] after armor 52.396205878187
[ATTACK ARCHERY] after range 52
[PHYS CRIT %] 27.3
[ATTACK ARCHERY] after crit 78
[ATTACK ARCHERY] after mult 127.99083598868
[ATTACK] mace accuracy bonus 58 16 = 1.042
[ATTACK ARCHERY] after hook 133.3664511002
[LOG] #{bold}#Jojo's Venomous Strike performs a ranged critical strike against Norgos, the Guardian!#{normal}#
[LOG] Jojo's Venomous Strike hits Norgos, the Guardian for #{bold}##LIGHT_GREEN#88 nature#{normal}##LAST#, #ROYAL_BLUE#16 lightning#LAST#, #PURPLE#8 arcane#LAST#, #ROYAL_BLUE#6 lightning#LAST# (117 total damage).
[LOG] Norgos, the Guardian uses Beckon.