Same here with duplicate entries for each leg.
MyFlights also alerted me to a change in my seat for the final HEL-LHR leg from "3C confirmed" to "3C unconfirmed" about a fortnight ago. I'd reserved it via web chat with AY back when I booked the ticket back in May. BA MMB shows no seat allocation at all for that leg although it does for the outbounds. If I go into the booking via the AY website it still has the seat reservation as before so I'm ignoring this for the moment, but has anyone else had the same issue?