Nikon Z 5 Reference Manual page 352

D
When [On] Is Selected for [Silent Photography]
Selecting [On] for [Silent photography] disables some camera features,
including:
•
ISO sensitivities of Hi 0.3 through Hi 1.0,
•
flash photography,
•
long-exposure noise reduction, and
•
flicker reduction.
D
Interval Timer Settings
Turning the camera off or selecting a new release mode does not affect
interval-timer photography settings.
C The Photo Shooting Menu: Shooting Options
310