A few days ago I had a post about my issue with OCBC 365 card not showing the transactions on my phone, and I think I figured out why some of my transactions didn't appear.
For OCBC, it seems like they have only enabled transactions made via your phone to appear. If you also have an apple watch (which I do, and used to pay for those transactions that didn't appear), payments made using that apple watch will not appear. As apple pay on your phone and apple pay on your apple watch have different device account number (security feature) even they are the same card, only payments made through your iphone will appear.
This is unlike AMEX, where ALL transactions made by the AMEX card will appear. I paid for a dinner via the old fashioned way and was surprised that the notification for it appeared.
So it depends on the bank's policies. I honestly prefer AMEX's way it's easier to check past transactions...