The problem was, most likely, that the statue is so large, and since the only thing solid really is the base, that the head passed through the ceiling of your lower floor and appeared on your first floor. I wwould suggest either replacing it or leaving it, since that actually sounds pretty awesome
I have actually seen this in other housing items. I have the metropolitan (i spelled that wrong i think) manner and it only has an outdoor space of 50 items. I place my outdoor items indoors and i have noticed 2 things pass threw the floor.
1: My marlebone flag. It is simply ment to be outside and passes threw the floor.
2: My dragonspyre Dragon head. The exact same thing. It is not solid (except for its bottom) so it goes right threw the floor.
I am aware other items do this. I think it should NOT be fixed because i need to put these items in my house :P.