Shield won't block in offhand after being hit by piglin

This just started today. I'm using the Pure BD Craft resource pack but I also checked Vanilla. I've been making a very long nether ice rail and a band of piglins spawned. Got hit by one and I Ducked to block but the shield didn't come up and didn't block any of the attacks. Checked Vanilla and same thing. Seems to be only the piglins and if they got an attack through.