What version? Are they really meshes or are there just dividing lines on the surfaces of the objects? There is a setting for controlling the number of divisions across a surface, which by default does not make them show. If you change that value, it can show many division lines and look kind of like a mesh. If you select the object, go to the Inspector window -> Object Properties -> Display, you will see there is a field where you can input the number of Iso lines. The default amount for Iso lines for new objects is in the preferences menu.
Otherwise, I'd have to see a file to be sure of what the objects really are or aren't.