Something happened with the winter update with the fix of pally unbending. I personally use the no-shield to tank a smash or bolt, but after the update I get rare occasions where the 99% shield is not actually blocking the hit and thus killing me off. Trying to cause it myself with testing did not seem to let me trigger the bug sadly. But it does happen when it matters.
Another thing. I also understood from other pallies that the shield cooldown is slower now than it was before causing the shield to not be back in time for the next tankbuster of mistkeeper.
Lasty, probably unrelated but maybe not, I noticed with multiple new pallies that they do not seem to be able to trigger their shield by holding their arm up unless they strecht it further then they expected. Didn’t notice any new pallies having that problem before this update.