Thx for the sweet reply, Vaanir.
Just because I have OCD, I''ll try to clarify with you - do you mean "No" as in "You are not using Apply poison", or "No" as in "Apply poison is not breaking stealth"?
Hoss, the only way I know of stealth being broken undesirably is when you get hit i.e. AE or Damage shield. Not sure if it pertains to specific type of procs.