I am not sure of this , it is just my opinion since I am not an Oregon  tax preparer .... the tax filing threshold may apply to a full year resident, IE apply to a full-year of income. Your client is part year and the income is only for a short period Of time. Annualized this income may be over the threshold. Also I think it is always a good idea to file even if no taxes are due just to let the reporting entity know of that fact. These are all just my opinions as I am not an expert on Oregon