This problem goes back many years if you search on Google.
Fios internet connection momentarily drops to router (wired and wireless at same time). Too brief to activate red warning on router but work interrupted on all devices until app closed and reloaded.
Tech support no help. For me, as with other customers, Fios replace router and ONT unit which did not fix it.
Problem is the router setting for DHCP Lease time reset. My quantum router was had default value of 60 seconds. When it renewed the Lease all devices cut off.
Solution is to go into router software from web browser and reset DHCP Lease renewal time to one day (in seconds). Longer would be best, but that is the maximum allowed in Quantum settings.
Shorter Lease Renewal times only needed in crowded networks with many people signed on to same connection. Too many inactive connections tie up the lease.