Medical Travel Assignment

Yes.

The general rule is: your report all your income on your home state return, even the income earned out of state. You file a non-resident state return for the state you worked in and pay tax to that state. Your home state will give you a credit, or partial credit, for what you paid the non-resident state. You will have to file a non resident OR state return and pay OR tax on the income earned there.. You will also file a CO full year resident return and calculate tax on ALL your income. CO will give you a credit, or partial credit, for the tax you pay OR. So, there will be little or no double taxation, but you have the cost and hassle of filing two state returns. Do the nonresident state return first.

During the period your employer is withholding OR tax, they SHOULD lower the amount of CO tax being withheld.  But, employers don't always go to that trouble. If not, you'll get it back when you file your 2022 CO return.