Shock is the current autoseller's theme of the day, and the next Vanaduke gate is going to launch tonight. The autosellers might get different minerals to make a different theme of the day for the next gates, but we're going to have to step in ourselves to change Copper Bishop.
Pushing Yellow above Blue seems to be our best chance in all of the strata, as this will give us anti-Undead and thus a randomized gate. Red is also valid for strata 1, to make it (anti-)Fiend. If we can make it so Blue, Yellow, and Purple each give two crowns in the lower strata right before the gate launches, it might stick.
(This might also be an early call for an alloy, and maybe a closer look into mineral spawns in general. I don't think OOO intended for this change to make the gates look like a crappy weather report.)
I don't think it's autosellers that are making the gates all shock themed, we went a few days with the new system and all the gates under construction save the two people were trying to make a certain theme all the way were fairly mixed up pretty quickly, the all shock theme thing is new, and seems more likely to be the doing of someone or several someones purposely making everything shock themed.