Is it safe to use a 2 burner reversible griddle on an electric stove?
I would think that this setup is not causing a safety issue.  Since you are not using a gas grill, there is actually less to worry about with it being flush, as there is no burner to potentially snuff out, which would cause a gas buildup.  Also, Lodge's website states under the Use And Care tab that their reversible griddles are good for any stove type, and do not have warnings against using it in such a manner, you should be fine.

From my experience, these are perfectly safe, although you will want to make sure that you have your heating coils (if you have them) flat and flush with the burner trays, so that you achieve optimal heating and ease of use.