Mine was opposite....I got update on my Ecas about IRCC sending my oath letter (ecas stated date and time,letter should tell you further info) and didn't receive my letter in time.
A week after my Ecas update,I called the IRCC call center number....the agent confirmed that I am indeed scheduled for oath and that I don't need the actual letter since I am in the official list. She then emailed me the other specifics of the oath letter contents.