Well I think I finally figured out why this was happening ... looks like Synchrony has a patent on "dual card" schemes. Macy's issued two separate statements which I thought circumvented the patent, but maybe not? Either way, I don't really care that much as I'll take 5% cash back using my USB Cash+ card and not have do fiddle around with the 5% back in "Star Rewards Dollars"
https://patents.google.com/patent/US6915277B1/en
