This is not uncommon. Depending on the states involved and your employer's payroll reporting system, your earnings can be reported to more than one state, either in whole or in part.
Employers are often required to report the same earnings to more than one state, either because of a move or when you work in one state but live in an adjacent state. It is up to you to properly allocate the income to the appropriate state/s in the income allocation interview of your state tax program/s.
What should not happen is for the employer to duplicate amounts of state tax withheld (Box 17 amounts).