Sounds buggy, as far as I know what your experiencing isn't even a modelEditor command which is what is used to set the shading modes of your viewport.

It sounds like there are confused matterial assignments.

What happens when you apply a new matterial to your object?

Is this happening on all objects ? Try making a new random object and see if this effect still occurs? Does this happen in a new scene?

Also ensure there is only one shading group / matterial connected to your object in the hypershade. Also make sure there is one in the first place. Objects tend to display as wireframe regardelss of viewport settings if there is no shading group linked to the object.