I highly doubt that's a regurge, honestly. You would KNOW it was a regurge because it would stink to high heaven. You would be gagging. That is poop, I couldn't tell you why it's not fully digested, but I think I can pretty confidently tell you it's not a regurge. There is no mistaking it for poop, lol. Plus, I see a urate.
Snake poop can look very much like human poop, poop is poop for the most part.
Up the food size, and see how the next poop is.