Paying Oregon state tax as a Nevada resident.

I just started a new w-2 job as a traveling field technician. I am a permanent resident of Nevada. I received my payroll check and it’s listed I paid Oregon State income tax. Why am I subjected to pay their  state tax? Do I address this with my employer? perhaps there has been a mistake? If it’s not a mistake, how do I recoup any state tax I paid to Oregon? My work is performed on the road in different states.