Not normal. Take them back to where you bought them and hopefully you will get a full refund and buy something else. Very strange indeed. No idea why,moisture,old, factory error? Hope the place you biught them from understands. I know they are expensive and sighting a slug gun in is zero fun! Everything else you have is top notch, you should expect some excellent accuracy and beleive me, a one shot stop!
I look forward to more info on the new ammo.
Chalk this one up to one more strange solution,hopefully!