Originally Posted by B747-437B

In this specific case, I cite CAAP CAR 8.11.1.4 (a) which explicitly states :

The Authority will consider all time spent on an aircraft as an assigned flight crew member or relief flight crew member, whether resting or performing tasks, to be duty aloft.

In response to the OP, while standard CAAP CARs would not permit this kind of operation, presumably PAL has obtained approval for a FRMS based FDTL system which could enable this kind of operation under specific conditions. In current pandemic circumstances, this is actually fairly common and is usually mitigated by additional rest periods both pre- and post- flight to compensate.