On my Z1Compact the tiny membrane visible over led seems to be connected only on two sides, leaving the upper side merely close up to the plastic frame. From a close observations is possible to see a space small enought to insert a slim piece of 3M Scotch (i've noticed the first time during the first led blink).
I suppose the led underneath and the earpiece are water shielded otherwise: because i have already tested twice (for a total of 10 min.) on a water recipient whitout visible infiltrations or failure.
On the teardown photo this area is non visible.
Do you have any news concerning it?