The minecraft wiki articles linked may not fully match the mechanics of the current server minecraft version (1.12.2, 1.16.5)

Changes

Dusk stone armor no longer gives the saturation potion effect as it is too overpowered for survival minecraft, it allowed people to heal almost instantly with only the armor equipped.

The dusk stone armor effect now gives half a food bar and 0.1 saturation every 10 seconds and counters the amount of Exhaustion level increase. This means the dusk stone armor will still keep you fed for the majority of actions, but wont allow you to heal fast while also doing intensive actions like sprinting and jumping.

The goal of the dusk stone armor is to keep you fed, not make you invincible, and we feel these changes do as best we can to reach that goal in a more balanced way.