As the title says, I'm having a bit of trouble with shield bash. Since I've entered Stone Vigil, I noticed that I can't stun any of the bosses out of their attacks with shield bash. The attack would connected, and I'd time it right but the boss/mid-bosses would just resist it. And after that, I did my level 44 quest for The Maelstrom, and the same story. I could not interrupt the boss's attacks at all.

Is this normal? Are the level 42+ bosses all resistant to stun? Because if they are that's a pretty hard hit to usefulness as a paladin.