Peak lapels on an odd jacket are out of the norm, they're different, they indicate that the wearer marches to a different drummer. To assert, however, that peak lapels on an odd jacket or a single breasted suit are wrong or violate some rule is simply to be seduced by the siren song of prescriptivism. I think the urge to make up rules and then attempt to apply them to a wider community is a basic human instinct. It has happened over and over and over in human history.
There is nothing wrong whatsoever with peak lapels on an odd jacket or a SB suit. It can look very elegant and somewhat rakish. Whether you like that or not is purely a matter of taste, of opinion. Nothing more.