Nikon Z 8 Reference Manual page 448

The option currently selected is shown by an icon in the display
during shooting.
D
Cautions: Active D-Lighting
Depending on the subject, "noise" in the form of randomly-spaced bright pixels, fog, or lines may
appear in photos taken with Active D-Lighting.
In mode M, [Y Auto] is equivalent to [Q Normal].
Uneven shading may be visible with some subjects.
This function does not apply at high ISO sensitivities (Hi 0.3–Hi 2.0), including high sensitivities
selected via auto ISO sensitivity control.
448
Active D‑Lighting