This is just one example, every transaction appears to follow the same pattern of taking *at least* 4 hours before they are visible.

I got a verification (by email) of a new donation, with transaction ID; XXX123 - Timestamp: 6 June 2018 at 07:30:42 GMT+2

I can see this transaction in my activity log when I login to PayPal.

I CANNOT see this transaction, wither with:

https://api.paypal.com/v1/reporting/transactions?transaction_id=XXX123

This just returns 0 results.

Or with:

https://api.paypal.com/v1/reporting/transactions?start_date=2018-06-04T07%3A05%3A01%2B00%3A00&end_date=2018-06-07T07%3A05%3A01%2B00%3A00&fields=all&page_size=300

This returns results of other donations that are more than 4 hours old.

Why does it take so long to show up in the SYNC API results?