I have a YVR-EWR trip booked over the holidays which has an odd display appearance on aircanada.com

It was ticketed way back in the summer, and there have been a couple of schedule changes (minor adjustments of 15 minutes or less) since ticketing.

Now that the Christmas holidays are approaching, I've checked in on the booking via Air Canada's web site and noticed an anomaly. While the outbound leg looks as expected, the return flight AC 549, appears twice under "Details" of my booking. Two 787-9s appear on the screen with the exact same timings for arrival and departure.
Also, under the "Seats" column in the booking information that follows my name, the flight number appears twice - once with the correct seat allocation (Premium economy) and once with no seat indicated after AC 549, just a dash ' "-"

Do FT sages see any significance to this odd display of my return flight display? Is any preventive action called for on my part?