I think they may have actually screwed things up beyond reducing the prestige of that stuff. For example, I just placed some Sedimentary Bricks and it added 0 prestige.
Nm it just took about 20s to update on the beacon.
EDIT: After testing, Gleam now gives around 16 prestige and Refined Gleam, which is what a lot of my plots are filled with, gives only 20 prestige. They cut gleam to a 1/3rd of what it used to give. Welp, that completely wrecks my build :(.