Ritual Map with no Rituals

I spawned into a t15 map (Hidden Grotto) that was suppose to have Ritual alongside some other mechanics. All mechanics were present EXCEPT Ritual, explored the entire map. Other mechanics were, Breach, Delirium and Abyss (overran).

Had the same happen to me just now. Lofty summit map with abyss, ritual and breach. No ritual altars in sight.

Ritual does not currently work on overrun maps - as all natural monsters (those spawning at the start of the map) are assigned to the abyssal cracks. As Ritual only works with the monsters spawning inside the ritual circle on map creation - this would mean that there are simply no monsters to kill within the rituals (unless rituals always spawn alongside abyssal cracks/pits).
That is probably why they disabled rituals on overrun maps.