This is one of the age old philosophical questions, if you pooped and there was no poop - Did you actually poop?
A question that stumped philosophers until the late 1900s and the invention of the water closet and scientists accidentally discovered the ghost poop - You know you pooped but there's nothing in the bowl!
The quantum state of having pooped and not having pooped can be superimposed even in a simple 4D universe like ours and in the end it's just like the observer effect (double slit experiment):
If you checked and there was no poop, there never was any poop.
If you flushed before you checked, there was always poop there.
If you have any other questions feel free to ask, I have been called an expert shitposter by people with vast experience in the field.