If you are a Minnesota resident, and you never actually (physically) worked in California, then your W2 wages or salary are not subject to California taxation.
As a Minnesota resident, ALL your income is taxable by your home state of Minnesota, regardless of its source.
If California taxes were inappropriately withheld from your pay, at year's end you'll have to file a non-resident CA tax return, on which you allocate zero income to CA, in order to get those taxes refunded.
CA can only tax a non-resident's W-2 income if it was earned from work actually (physically) performed inside California.
From CA Publication 1031, page 6:
"Wages and salaries have a source where the services
are performed. Neither the location of the employer,
where the payment is issued, nor your location when
you receive payment affect the source of this income. "
https://www.ftb.ca.gov/forms/2020/2020-1031-publication.pdf
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
