Dear Yong Peng,
As I see it, kaayassa bheda denotes that the living body has become corpse.
As Ole says, a fundamental change.

When alive, the ruupas of the body originate from kamma, citta, nutrition
and heat. The ruupas of what we call a corpse originate only from the
element of heat.

Ole quotes Dhammapaala: "Now Dhammapaala is more explicit, he suggests that
it means to give up the khandhas and adds the alternative explanation "by
annihiltion of the jiivitindriya" namely the life principle."
The ruupa that is jiivitindriya is to be found only in a living body, it is
a ruupa produced by kamma, and it arises and falls away throughout life.
So, I do not think that the PTS translation is so bad: breaking up. We could
say: perishing of the living body.
Failure also denotes this, like a machine that does not work anymore, but in
English failure sounds strange to me. Maybe we can find another expression?
The last consciousness, the dying-consciousness, cuticitta, falls away and
is succeeded by the rebirth-consciousness, pa.tisandhi-citta, which is
produced by kamma. If rebirth is in a plane where there are five khandhas,
kamma produces simultaneously with the pa.tisandhi-citta ruupas that will be
the new body.
****
Nina.