So I clicked the "All" button in my "Your Deck" screen, and the last card (In my case, Druidic Staff) showed up as 1.
I freaked out for a second and when everyone checked, I heard they all had "1" as their last card as well.
Since I have 6 druidic staff copies, I went to life element and there there were 6 copies as usual.
Playing around with the "all" cards -
1) Last card in "All" will always show as 1 copy.
2) If you add enough cards from "All" as to make one more card show up, such as adding 6 of antimatter or anything else in your deck, the card in question will go up and a new card will be the last one. In this case, the card that had 1 and went up will show it's original amount of copies, and the new card will show as "1".
3) If you try clicking the card that shows as 1 copy, a copy will be added into your deck and the card will remain as 1. You can keep adding it until it goes all into your deck and the next card shows up, or until you can't add no more (over 6 copies of a card).
Really minor.
Thanks fippe for the pics.