Prethoryn scourge occupation bug

[LorD_FerDiNaND]

Hi guys,

So I understand that this is an issue, I am playing on an Ironman game and this bug seemed to happen where I have almost wiped out the scourge yet there is an infested planet I occupy yet I cannot cleanse.

I have tried fighting others so that their fleets do devastate the planet enough but to no success.

Is there a way this can be fixed or something can be done in order to have the achievements and not modify my saves?

Thanks all

 

[Zagreb 887]

You can try to crack the planet with a colossus.

 

[LorD_FerDiNaND]

You can try to crack the planet with a colossus.

I already have all the perks and cannot select the colossus proyect. Maybe something else?