Why is that suspicious? You have a credit card bill, you then go pay your credit card bill at the branch location. My neighbor ONLY pays her Citibank credit card this way. In fact, except for Discover card which has no bank branch, she pays all her credit card bills personally at the branch - Citi, Chase, BofA, you name it.

You would be surprised that many many many folks actually still use cash.

And yes, Citi is real time. The moment you paid your bill at the branch, it reflected in your online account activity, much faster than Citi posts the charges.