I've kept and bred many large constrictors in the past...both boas and pythons, but never any Australians...and that behaviour was very common with all of them. Just make sure that the temperature is adequate for proper digestion...and I'm talking about the temperature of air, water and substrate.
In fact, if you're lucky, you may have one of those individuals who like to defecate in the water. If so, and if you can adjust your set-up to make it easy to remove and clean the bathing container, it makes removal of big messy BM's much easier and much less unpleasant (note that I didn't say "pleasant"). Then you simply adjust your feeding schedule to ensure you're home when the big event occurs...they're usually like clockwork after a decent meal...and life will be easier, cleaner and far less stinky.
Whatever you do...once you learn how long it takes to produce a poop after a normal meal...DO NOT feed unless you know you can be there to attend to it immediately. If you aren't and it sits for any length of time, that would be...bad...
As an aside...back when I bred snakes, this would have been a "Children's Python". Apparently since then, it was assaulted by the Splitters and separated out as its own species, Stimpson's. And now, apparently, the Lumpers have regrouped and tell us that it is indeed just a form of Children's once again.
Taxonomists...pppffft!