tainted rusher

While I do like the concept of adding a character who slowly mutates throughout your adventure as a parallel to some character's you've probably played or are playing as, I have to ask the obvious. Why was there never an option added to help her? I'm sure this was answered, and I can guess the...

Is tainted rusher encounters one per planet I only got one in mhenga and tarkus right after i got the probe, roamed for days couldn't get more or is it because I am playing the kineticist class.