Not sure if it’s a glitch on your end with stale fleet information, or on Delta’s when they’re filing the plans (or something else entirely as I don’t have any handle the mechanics on your end), but, I’ve picked up information on several DAL flights with B739’s showing up as B735’s via FXML3 / AirportBoards.
Frequency on this was very high July 30 - August 3, but a few have been trickling in since then; tails I’ve seen it on since August 3:
flightaware.com/live/flight/N880DN
flightaware.com/live/flight/N871DN
flightaware.com/live/flight/N869DN
Thanks!