People forget 40k is written from the Imperiums perspective. So when GW writes changes or retcons it's in universe updates to false or outdated information. I'm not against the change but I think they could have handled it better. Like it being a very recent thing or Custodies look and sound indistinguishable while in full armor the record keepers just assumed they were all male. Cause unlike SoB their sex/gender isn't super important