"Incoming webhook" type automation triggers changed their base URL and have a new undocumented "Secret" parameter (randomly?!)

Hello guys,

we have just switched to create incident tickets for our addon “Jira Email This Issue” by firing a webhook against an automation in Jira.
It basically works, the automation is triggered, we can parse each attribute in the transmitted JSON.
The addon webhook itself gets a strange response though. It says there “no JSON input found”.

In the addon, we do not use the https://URL/SECRET trick, we past in a custom request header section the two lines for Content-Type and X-Automation-Webhook-Token.

Does someone gathered experiences with that behaviour in the connected apps and why it acts like that, since the automation is triggered correctly?