For such cases usually occur on travel merchants (it can be from non-travel Merchant's too) as most of the travel merchants (e.g Expedia, Hotels.com, Accorhotels.com, etc.) will only validate your Cashback after your check out date and it depends on the time frame that has been set by the merchant. You can refer to our terms & conditions like below.
In other situations, if your Cashback is tracked at SGD 0, the final amount will be updated upon validation. This can be found on our terms & conditions too!