Now that you mentioned it, I did also notice that my Mundus stone seemed to disappear on my template character, so I went to go get a different one, but I didn't check to see if it was on my character sheet. I'll have to log on tonight when I get home to have a closer inspection.

Could this just be a UI issue, something related the change in the patch notes where we can't see long buffs on player characters unless cast by a player?

Can you try get the Mage Mundus, record your Max Magicka, and then switch to the tower and see if it changes?

It is a UI bug . You still have your Mundus . You will have it if you just got it and it will be gone from your character screen once you teleport to another area .

There is definitely something wrong with Mundus stones. I made a set of twice born armour. Equipping it seemed to remove all mundus stone effects. I went to the apprentice and got that. Liquid lightning went up from 2481 to 2690. Then I went to get the thief. A bear attacked, and then I was unable to interact with the mundus stone. Character showed no mundus stone active, and liquid lightning had gone back down to 2481.

I had the same thing with another character earlier this week. When attacked at a Mundus stone, it then became unusable. I didn't check the spell damage on a skill at the time though.

I came to the forums to ask about this, but saw someone had already done that. I hope it's just the PTS and not the live servers...