I had something similar happen on an AC flight to CUN. Traveling with family with me on revenue and the rest on redemption. Both itineraries were “cancelled” by text message and email. The flight status said cancelled on the app but the call centre said everything was fine. In the end it was a change in flight number AC930 became AC928. Same time and everything. No idea what it was all about but I’m soaking up sun now in CUN so don’t care!! 😂