Or perhaps it’s decided when the portal is opened not necessarily coded in waystone itself.
Btw I found this:
mods/gdx2/resources/scripts/game/questevents.lua:905: startEndlessDungeonShard80 = gd.endlessDungeon.core.startShard80,
mods/gdx2/resources/scripts/game/questevents.lua:911: startEndlessDungeonShard80NoLoot = gd.endlessDungeon.core.startShard80NoLoot