I did not receive my full Oregon State Refund, I was expecting $634 and only received $323, can someone please explain why?
No we can't. Neither states or the IRS will tell anyone but "YOU" why you got less than expected. Generally in such situations you can expect a letter from the taxing authority that reduced your refund, in about 4 weeks explaining what they changed on your return, why they changed it, and what actions to take if you dispute the changes. All you can do is wait for that letter at this point.