Place surface on bed changes the entire 3D model

[drummerdimitri]

I tried to print this box https://www.thingiverse.com/thing:2429908 but since it required too much support material, I decided to change its orientation so that the top is placed on the bed but when I did so, it changed the whole design of the box but I didn't notice that and it printed incorrectly. What is going on here?!