Thanks - it's good to know. I have new cc's that I can apply those purchases to. But Discover cashback for the purchase isn't a total waste, so I don't feel too bad at this point. I'll definitely keep it in mind for the future.

For example, two of my purchases were rental cars. I'd much prefer to put the charges on United Explorer due to their insurance. Luckily, no issues, but I'll be using that card in the future with ShopDiscover specials.