Bernadotte had never an order to support Davout, neither Davout to support Bernadotte. the Prince de Ponte-Corvos units were placed to march via Dornburg and that is exactly what Napoléon did want.
The Prince de Ponte-Corvo could not disregard his orders only because Davout - hypotetical - was asking for support, there he must still assume that the main battle was fought at Jena and not at Eckartsberg, Petre - as well as Chandler - are just not critcially refelcting what orders the marshals had and what they did know before the fight started.