Quite a few people have had similar issues.
Pics of Berger Bullets NOT Performing????
Have you managed to recover any of the bullets?
How were the animals struck were you penetrating any dense bone or just through the ribs?
One reason I don't use hollow points at all for hunting game (as opposed to predator hunting) is because I've seen too many such problems of either not opening at all and punching straight through, pretty much exploding with little or no penetration, or having them basically turn inside out and poss through base first again, just punching straight through with little to no internal damage.
Read through that thread and you'll find that the folks at Berger are aware of the issues and working hard to resolve them.