Were that the case they would have said that directly, like they did with Haunted Tower and Eternal Elemaugrim which did follow a structure of team X every Y battles.
compare the description of Werebat’s event which was structured almost identical to this:
World Event: Dark Moon Rising
There are 5 battles that players can encounter during the event: Vargouille, Werebat, Sanguinia, Crimson Bat, and Draakulis. The battles are randomly chosen, but they all have an equal chance of appearing on the map. The battle against the Werebat is a rare battle that may appear on the map, but only 1 Werebat will ever appear at a time.
And note, 1 in 6 is not exactly a “rare” appearance.
I think the intended reading is that of the six possible teams to fight, the “first 5” refer to (a) Spirit Fox, (b) Fenrir, (c) Forest Guardian, (d) Kerberos, and (e) Wulfgarok whose encounter rates are equal to each other, while Inari is a rare battle that may appear, but only 1 at a time.
…or to phrase it in RNG terms:
- Each team (other than Inari) has a 20% chance of being selected
- On rare occasions one Inari team will appear on the map
I think the issue here is how they prepare the official posts: they seem to list off the possible teams in Base Rarity order, when sometimes it’s not the Mythic team that’s the designated “rare” encounter.