Townhome 2nd floor is uneven

[Herbert Wu]

I am looking at a foreclosed townhome(30-year old building) where ground floor(no basement) is main entry door and garage. All rooms are on 2nd floor. But Kitchen/Livingroom/Bathroom/hallway all have uneven tile-surfaced floor - either sloped or wave-shape. Is this a possible structure problem or just bad tile work?

Thanks

Herbert