Is that any way can scavenge get the parasite from Vault or any room of the latest level?
since the latest level dont have any office can scavenge, so basically it can not test corruption level 6 effect of the parasite,  unless you carry the parasite from previous level,
however, the parasite will be gone after the corruption level increased,  so it will never show the corruption level 6 effect of the parasite.
since last level is only can reach corruption level 4. even carry the parasite, it will never have chances with corruption level 5/6 + parasite effect.
also, after disable the corruption level in cheat menu, the parasite's effect(increase corruption ) will still working .

We didn't add any area where you can scavenge in Chapter 3 at the moment.
I will have a look at the parasite effect, it shouldn't be working if corruption gain is disabled.