I documented the issue, linked Hubspot's API docs confirming it, submitted a ticket through their normal support portal and had a confirmed bug from a Zapier engineer within an hour. The fix was live before I came back from lunch about an hour later.
This is why they're successful. If I submit a bug report in Blink (usually major text rendering/CSS issues), a Google employee will look at the issue a month later, maybe. If I submit a bug report in one of their APIs, if it isn't Adwords and isn't customer impacting, the response is basically a middle finger/"we will fix never".
Zapier made a lot of my contracting work way easier and often I get the client involved and they become self-sufficient. Zapier should pay me money! kidding