If she was actually domiciled in CA all of 2019 (her main home was actually in CA all year), then for state tax purposes she would be a full-year resident of CA.
If she abandoned her home in CA in 2019 and relocated to a new main home in FL, then her domicile state would have changed to FL after the move, and she would be a part-year resident of CA. See "Meaning of Domicile" on page 10 of this California tax publication: https://www.ftb.ca.gov/forms/2019/2019-1031-publication.pdf
Another way to look at it is that a taxpayer cannot claim to be domiciled in a state in which they have no home. Otherwise anyone could claim to be domiciled in a no-income-tax state like Texas.
The only exception would be active duty military, whose state of domicile for tax purposes does not change when they relocate to a different state due to military orders.
State of domicile is determined by tax law, not by employer requirements.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
