How does the passive Made to Last work?

The passive reads "15% of Physical Damage prevented Recouped as Life". I translated that as below, is that correct?

When taking physical damage, 15% of the physical damage is essentially mitigated, and the 15% damage that you would have taken is recouped as life.

Think it’s more like 0% dmg prevented and recoup that damage over a 8 second window

People with high Life regen have reported that it barely even impacts their life regen

Dead stat

15% of whatever your armour (or potential other sources ) mitgate