When Maybankard 2 was launched not long ago last year, this was an issue which a transaction with posting date not on Saturday or Sunday was not eligible for 5% cash rebate although the transaction date was on weekend. By then, card holders had to complain to Maybank card center and provide transaction receipts as proof.
Now I checked back last 2 months' statements. There were some transactions with posting date and transaction date discrepancy but Maybank had fixed the issue. These transactions were eligible for cash rebates.
If you are still worried, you can keep the transaction receipts and calculate the cash rebates on the month's end to see if it is correct.