Where are " Delirium Fracturing Mirrors"

Hi, i got a question couse idk if its bug or feature.

There is no Delirium fracturing mirrors in game, but there are atlas points in delirium tree and also tablet affixes increasing delirium fracturing mirrors in maps.

Delirium fracturing mirros used to trigger when u walk on them knocking back spawning monsters dropping simulacrum splinters

They has been main source of simulacrum splinters.

I saw them once in act 4 delirium quest. But in maps they dont exist.

My question is is it intended, is it bug, or they spawn monsters instead delirium fracturing mirrors, how it works?