As 5 year old I used to poop on the floor at my Grandmas house.
I would not use the toilet at her house or other peoples houses but for some reason I would poop on the floor in a corner somewhere.
I'm not sure why I did that.
But my Grandma didn't seem to mind me pooping on the floor and she would just lovingly clean it up.
My mom and dad would get mad at me but my Grandma told them that it was fine and that I was probably just afraid of using other peoples toilets.
That was probably what the reason was.