I'm actually a big fan of that decision.
The idea that non-binary people have to visibly appear non-binary is a harmful stereotype. Murderbot's physical appearance is a part of its design that it has no control over. Why should it look androgynous? Just because it perceives itself as genderless, doesn't mean it's creators did.
I hope the show will actually dig into that at some point. I think it's really important for people to see an agender character who still has a strongly masc appearance.