I am not sure if I can help much but can share my personal experience.
I have used powder makeup for over 10 years but in the past couple of years my skin has become more acne prone and I think the powder mineral makeup is contributing to it. The one I use doesn't contain corn starch or rice starch, only mica, kaolin and titanium dioxide. I am not sure which clogs my pores but I have read online several views that mica can be pore clogging. I find that most sunscreens break me out, so possibly the titanium dioxide is a problem. I am not sure.
My theory with powder mineral makeup is that because the particles are so small they get into the pores more easily where they soak up oil and clogs your pores.