Trying to understand how loop decay actually works

Is is just me, or does loop decay only decay the loop when you are actually playing something new in overdub mode? When I have loop decay at say 40, and I put it in overdub mode, but I don’t play anything, the loop doesn’t keep decaying upon repeats.

With overdub engaged and loop decay on, what I would expect to hear is a drop in volume with every repeat of the loop, until finally it is basically silent. That’s how my Gibson Echolplex Pro functions (on that pedal this feature is called “feedback”). However, on the Aeros I have waited several minutes while in overdub mode and loop decay on (at a moderately high value), and yet the loop doesn’t seem to keep decaying.

Anyone else experienced this? What am I missing here? How does loop decay actually work on this pedal?