you should first find out from your employer why Ca tax was withheld. if you still work for them they may have withheld Ca taxes for 2020 and are doing so in 2021. Ca does not tax telecommuters. people who live outside of CA but perform work for Ca companies
ask the company if they'll refund the Ca w/h. they'll need to issue corrected w-2's that show no Ca wages. and no wi/h if they make the refund. you also wouldn't need to file a Ca return. if they refuse to refund the w/h then you'll still need the corrected w-2 and then file a nonresident return to get back the w/h. you will not be filing an amended Ca return because apparently no original has been filed.
