prevent damage and ridiculous pack dupes

Firstly, prevent damage has been causing none of my destroy spells to work, causing the 3rd node of trial of zeal to be nigh impossible as I don't have enough lifegain in the new sets. I don't know if this is purposeful, but I really hope not...
Secondly, I bought the 600 crystal white week pack (consists of 2 premium packs and 1 white pack). In the first premium pack, I got a total of 7 'shred weakness's, 3 of them in a row in one of the packs. In the second I had better luck but still got 3 sets of pairs that showed up next to each other in the same pack. I don't know if this is just RNG nonsense or if there is a glitch.