Trailers for 1.85 films were sometimes formatted to match the aspect ratio of the 2.35 films they were intended to be attached to. When they weren’t, a projectionist had to manually switch lenses on the projector before the main feature or else the image would be distorted. I would often see the lens switchover if the projectionist wasn’t fast enough. Digital projection and automatically controlled adjustable height screens has done away will all of this of course.

Since Spongebob was animated digitally, it’s possible they went back to the original files to make the trailer, the same way Pixar made a 1.33 version of A Bug’s Life. Some shots may have also been redone after the trailer was made. Note the slight background differences here.

Does the Hasslehoff live action shot have more picture info?