Applying to Ph.D. as M.S. student but failing to complete M.S. after admission
I would say it depends on the offer/acceptance letter you receive. I know someone who was accepted to a PhD program while doing an MSc, but whose funding (scholarship) depended on him getting a certain final grade on his MSc. I can imagine situations where that is not the case, and where you are accepted to a PhD regardless of what happens with your studies before the PhD program begins.