5 patreons created pledges and the webhooks did not fire once.
The webhook only fired when I use the “Send Test” option in which it confirms that the run was successful, and that my code did do what it was supposed to.
I dumped the JSON data I was receiving and it did work as intended.
However whenever someone actually pledges on the page, it seems that the webhook does not fire at all. The JSON file I use for debugging does not get any data appended to it.
Temporary issues with webhooks are always possible - some issue/incident at Patreon, a temporary/frequent connectivity issue in between Patreon and your host/server, a temporary/frequent load issue at your server, security software like mod security, or security plugins filtering connections temporarily or permanently etc.
Contacting your host to ask them to have any IP that reverse-resolves to *.patreon.com whitelisted would be a good measure.