API Notification sending inconsistent information

We have an API notification set up to send information to the software Drip whenever somebody makes a purchase on our site, however the information that Drip is getting is inconsistent from S2Member.

We always get the member level but for example sometimes a users last name wont be sent, or a first name, or both. We’ve made sure that these fields are all mandatory on the the sign up form to ensure it’s not just a case of people not having entered the information.

We’ve also double checked with Drip to make sure it’s not a problem on their end. They’ve verified that it’s not getting the information from the API call in S2Member.

Does anybody have a fix for this issue?

I have never used the s2Member Notifications API. I recommend using WordPress’s own REST API instead.