While I like this work, the title may be misleading to people who think of "privacy loss" as something distinct from "differential privacy".

What they show is that as you use Apple's implementation, the differential privacy parameter grows (providing weaker guarantees as time passes). They don't show that they can bypass the mechanism and it's guarantees, just that Apple has rigged the implementation to decay the guarantees as you continue to use it (note: decay stops if you stop using Apple stuffs).