Two of the talents the Investigator can take are Sickening Offensive and Sapping Offensive. These are activated when damage is dealt to a studied target through Studied Combat with the caveat: "Only one of these talents can be applied to an individual attack, but the decision can be made when the damage is dealt."
So firstly, does this mean with iteratives you could apply sickening to one hit and sapping to a second?
And secondly, would sickening stack with itself? It applies sickened to the target for 1 rd. If you applied sickening offensive to 2 consecutive hits would it apply for 2 rds.? I don't see anything in the talent or Investigator Talents that says it does not stack, but I know often things don't stack unless otherwise noted.
EDITS: Clarity
no they don't stack with themselves to increase the duration. Yes you can change per attack.
Thanks for the clarity.