As the return goes thru "processing" there can be times when it's progress is not displayed and that is normal. Look/check again tomorrow. A lot can happen to a return between the ACCEPTED for processing tab on the IRS tool and the REFUND APPROVED tab. The return may get "side tracked" for some kind of review at any time as it travesl thru the pipeline and how long the review will take is unknown.
If you check too many times in one day you can be locked out of the system for 24 hours so patience is needed.
