This is incredibly important, and I posted a separate issue on precisely why it’s so critical here: WebHook API sending NULL last_charge_date, resulting in double rewards. MAJOR issue before I noticed it was raised already.
The short of it is that when processing webhook events, the last_charge_date is basically the only way you can differentiate separate payments, since a patron paying can often (though not always) generate multiple events. Right now with the date of ‘null’ my system is forced to think of them as separate, unique payments, resulting in double and even triple rewards which I then have to sort through manually.