It did happen, at least from the perspective of a one year member. We had zero warning, and even core staff were caught off guard. Our migration basically began now.
I agree. If this was Oracle I might not have too difficult of a time believing this is all of the story. But I do think in this case there is more to the story.
I am willing to believe these things do happen. Different vendor, but I have experienced a price jumping 3x with one month notice before the annual renewal.