With the addition of new mutation tree, this small change arrived as well. Strangely enough, you can still get rid of this mutation by getting fast healing etc.
Whats the reason of this change? Werent all pre-treshold mutations meant to be purifiable? Now, if you want to reroll all your mutations you just need to include medical-mutagen instead of purifier. And fighting Rat-Kings can give you this problem as well. From gameplay perspective, it seems to just incrase chaos of mutating, and restricts fun of pre-treshold mutation experimenting.
On the side note, because i am not feeling like creating whole new topic just for one idea. Shouldnt new tiny mutations (I am loving mouse BTW, very creative and climatic category) just decrase strenght by 1 or 2, or decrase strenght by 1 and keep some of weight reduction %? It seems strange that such small mutants can swing their sledgehamers just as good as before.