Why do you think the payroll department screwed up?  I often see state W-2s that split out the total federal amount, by state.  She moved to California from the Netherlands, but where was she a resident before she moved?  Is she a newly-arrived immigrant, or was she a US resident before going there, and did she maintain her US residence?

States have two methods of taxing part-year residents. 

Method 1:  Just pay tax on what you earned here, it doesn't matter what you earned elsewhere.

Method 2:  Figure the tax on your entire annual income, regardless of where it was earned.  Then apply to that total tax, the percentage of income that was earned here.  

The second method gets part-year residents into the higher state tax brackets, and so is popular with states like California and New York.