The creators of Path of Exile 2 recently introduced a series of hotfix updates aimed at nerfing Temples. Players have learned to build very profitable combinations, which not only affected the balance but also the game servers.
Now there is diminishing returns for the values of modifiers that rooms give. This effect will not work until the player has placed four or more rooms of the same type.
The developers explained their vision:
This change will have little to no impact on average Temple builds, but will have a significant impact on the top-end Temples. These Temples were causing serious server performance issues and often led to crashes. If you have enough rooms to trigger the diminishing returns modifier, it will first be applied to lower-level rooms so that your higher-level rooms bring maximum benefit to the Temple.
Also, a bug was fixed due to which more magical and rare monsters appeared in the Temples than intended, especially at low levels: "This change has only a slight impact on high-level Temples."
Full description of hotfix updates for Path of Exile 2 is published here.