No, actually it's not.
Hulk
(it's like I was born for this) survived the gamma radiation that would have left 99% of the population looking like creamed corn.
Monica was warned about her DNA changing after being in Wanda's hex...people were expecting Darcy to get some kinda powers when the same happened to her? Why not?
Because she was born with the capacity for mutation. Doesn't matter if the hex or the snap set it off, if others are largely unaffected, the ones that are were
born with the capacity to mutate.
Having different defintions in the MCU is redundant.
If you establish that the celestials (and possibly the high evolutionary) tamper with the life forms on the planets they seed, there is no real reason to split hairs between Inhumans, mutants and mutates as they are all a result of genetic engineering.