I would be inclined to think that whole area was once a walkout deck and that room has been added then closed in with blocks beneath —judging by the siding up against the the window frame in the corner and looks also to be a flat roof on the closed in area —unless there is some sort of flashing under the siding there is a potential for water damage around the exterior walls as mentioned —the deck area itself could have been protected with a membrane and has flashing... it raises a lot of questions. I would think there's only one way to sort it out and to look deeper if the space beneath is livable space now. I'm not an engineer but many things don't look right there.