See, that's where some people go wrong. They get gut matter on the arrow and assume gut shot and leave it go till like 8 hrs. or the next day. It's always wise to take a good look for blood, at least for a little distance. If you get gut matter mixed with blood on the arrow, you can be reasonably sure the liver was hit and the expiration time will be sooner than it being just a gut shot. This could easily happen, being a little off on a quartering away shot. In your case, the arrow did the liver damage first then departed through the stomach leaveing just gut matter on the arrow.
never say never
patience is the companion of wisdom