Hi Manychat!
Update (28 Nov): This issue has been resolved
We are aware of an incident affecting the deliverability of WhatsApp messages:
When a conversation is initiated through an Ad on Facebook or IG, the WhatsApp Keyword Trigger does not activate as expected, preventing the Automation from starting. Users must type the keyword again to receive the message. We are continuing to work on a fix for this incident.
Our development team is actively analyzing the scope and working to find a solution.
We understand the inconvenience this may cause and are making every effort to resolve it as quickly as possible.
Please check our Status Page for more information.