Ok, here is my best shot at explanation. Applies to both Infinity and Prime.
If you make an UPI/DC payment of 5000(1500x3+500) on Infinite or 3333(1000x3+333) on Prime plan in a day, you will get ₹100 (equivalent coins).
If you make this payment for the first time in month, it will show ₹100/₹1000 on rewards page. Consider you made the similar payment next day, your rewards will show ₹200/₹1000.
Ideally, the reward counter should stop at daily limit of ₹100, but in Fi (a bug or not yet a feature) doesn’t stops for a day, but stops at monthly limit.
Consider you made a payment of ₹10000 in multiple transactions on any day. Now the per transaction limit of ₹30 will apply, but say your daily reward which should have stopped at ₹100 and reward counter should show ₹300/₹1000 ideally, it will show ₹500/₹1000, but daily limit of ₹100 atill applies when Fi pays you on 5th of next month. So instead of ₹1000 you will get ₹800 because counter was inflated by ₹200 extra on a single day, which never gets paid.
They need to fix this, and stop at ₹100 for the day even though we make more payments.