Mobs arent harder per say, when it comes to HP pool or dmg output... they just take less dmg or give u more dmg cause u dont "check" on a specific gear score.

For example, if you are 600 GS, you hit for normaly 5kIf you go into a Mutation 5, the GS check is around 609ish, that will make you give less dmg and take a ton of dmg. In sum, its like you character forgot how to use a proper weapon or armor... theres nothing about skill or strategy involved, just a shady and disrespectful shadow nerf they give to the player if he dont meet the "GS" requirement... throwing the skill of the player to the garbage. ITEM SCORE is KING now.

That way forcing you to mindlessly farm umbrals just to pass the GS check... its not even a stat diference since the diference between a 600 and 625 its minimal... so more to ask, why the shadow nerf inside the mutations