You may have to ask your California employer (or CA tax FTB) or wait until 2022 (when you receive your 2021 W-2).
The general rule is that income is taxable where received or earned. You will receive it in TX but it was earned in CA and CA will probably consider it CA source income.
Bottom line: if CA is in box 15 of your 2021 W-2, CA will consider the amount in box 16 to be taxable by CA. Your employer will, most likely, withhold CA tax. Your chances of getting it refunded is unlikely.
