I have hit that a couple of times, and warned others here not to count on rounding to the exact minimum for these promotions. I still do not understand why they sometimes do this, unless the credit card fee (or RN rakeoff) is determined within each dollar (or $5) range?

If you were billed $24.99, then Rewards Network really has to go by that. Their hands were tied by the restaurant. You have learned a very expensive lesson as the entire promotion was quashed for you, rather than just a single individual component.