We're they only retconned because of Fox/Disney?

Currently reading House of M and got reminded of dialogue between Wanda and Magneto from Marvel Rivals about her not being a "true mutant".

Scarlet Witch and Quicksilver had always been Magneto's children while I was growing up. It was only recently I learned that not only are they not Magneto's kids, they're not even considered mutants anymore.

Was this retcon just to work around any legal disputes between Fox owning the X-Men/Mutant rights while Disney had the 'Avengers'?

If that's the case, Disney owns Fox now so just keep em as mutants.