Something I find strange about this case:
Surely the burden of proof should be on the people investigating the woman, to demonstrate that she acted with malice? It shouldn't be on her to prove that she simply spoke with the ordinary habits of language?
Most people, other than a specific cohort of youngish people who have grown into adulthood in the context of this ideology, are primed to allocate pronouns on the basis of sex and it takes a certain amount of persistent mental effort to keep doing the opposite (especially in a context where you have work requirements that are making demands on your cognitive resources).
In a way, this woman was fortunate in having a documented reason why she was finding it hard. But plenty of other people might also find it particularly hard and not have such documentation. Anxiety, menopausal brain fog, stress, etc., as well as various forms of neurodivergence. Do all such people have to prove that their language use was without any agenda of hostility? Why, seemingly, is no consideration given to the idea that the offence of 'misgendering' is only substantiated if there is evidence of hostility to the trans identity, and of an unwillingness to keep that hostility out of the workplace?