Yeah. This had me irritated way back already. I always thought distortion would bring out "harmonic issues" (I know, it's not a proper term by any means...) more than clean sounds, but the opposite is the case, it pretty much masks some of those issues.
But it doesn't stop there - some pitch shifters actually seem to work better post distortion. Which I find to be pretty weird as distorted sounds are pretty much harmonically complexed. Also, if you really wanted to emulate a detuned guitar, that obviously would have to happen straight after the guitar's output.
Anyhow, given how far we have taken technology already, it's quite weird that there's still no proper pitch shifting working well with polyphonic material *and* low latency.
Fwiw, while defenitely nitpicking, pretty much any pitch shifter is polyphonic as in that you can feed all of them polyphonic material. Just that the output of some will sound worse than others.