For the immaculate trial, a handful of people have run into this problem with the pressure plates not reacting to weight placed on them; I don't recall if any were using the Epic Encounters mod. However, bypassing the barrier that solving the weight puzzle removes would allow you to continue normally with the other trials (I tested this through to the end of the trial a couple times, in saves where this was the only place where pressure plates didn't work).
The latest game version is 2.0.119.430, as shown in the main menu. If you are using Galaxy, select the game in the left column, click More and select Settings, and either automatic updates will be enabled or a specific version will be selected (for example, there is an issue with the latest Chinese localization update that removes the novice/expert/master indicators from skill tooltips; if you don't need the Chinese localization, you can revert to '2.0.119.430 (A)').
