Ok, since I am not there and did not observe the feeding here is my experience. I may have had one or two "true regurgitations" in my entire time screwing around with reptiles. I have seen a couple in the wild, i live in Florida and saw an entire possum regurged and laying in my back yard. A true regurge stinks to high heaven. These types of regurges are normally caused by sickness, stress or temperatures.
What it sounds like in your case is the snake swallowed the prey and then spit it back up within a couple hours. This does occasionally happen if there is a sudden increase in prey size and sometimes because the snake thought it was hungry and really wasn't. I will see about two or three occurrences a year of this out of thousands of feedings. It is why I always recheck the tubs in the morning after a feeding.
Common advise would be to drop the prey size back down a bit and wait a few weeks to try again. The prey size from what you say, was not too big but may have "surprised" the animal. There is probably nothing to worry about unless it happens again. I would be far more worried if the prey had been partially digested.