Time of Need took so long time to reactive after switching weapon

I have Time of Need on for both my weapon set, but it seems a bug? when I got cursed as I swaped weapon, ToN never clear the curse after 6 secs, but 15 secs maybe.

Why?

Sounds like your second weapon set has some "increased skill effect duration" passive nodes picked, which makes time of need take longer time to proc.

nope, non of my weapons or passive set to any inc duration.

you can test as:

set ToN on for one weapon and off for second, see if you got cursed with ToN off and swap to on, how long it'll take to remove the curse( compress time support for ToN).