I think I've found an un-errata'd errata in the Player Core, on p. 411. Under "Instant Death" it states:
"There are ways in which you can die instantly, without reaching dying 0 first."
I think the intention was either "0 Hit Points" and / or "dying 4".
On the same page above, it's noted "You lose the dying condition if it ever reaches dying 0", so dying 0 as related to immediate death makes no sense. On the following p. 412, it expands on ways you can immediately die, mentioning both "0 Hit Points" and "dying 4".
That said, the paragraph on p. 411 is likely unnecessary, given the following examples of Death Effects (including immediate death) on p. 412.
