I suspect due to colder weather and because of more erraticness. We've had some colder stretches and we're now experiencing more sudden cold snaps deeper into Spring. Latter situation especially bad if a plant is coming out of dormancy and then experiences freezing temperatures.
“Not winter hardy in our new climate”
Kind of a “buyer beware” type thing for long time customers used to buying these plants that while previously dependable perennials now might not be.
Really disturbing stuff to see.