Hi, 

I'm trying to setup a process in Process Builder that sends an email to a a Lead.

The related email template contains fields such as {{{Recipient.FirstName}}}. The process operated on updated leads.

When updating a lead I'm getting the following error message:
Review the errors on this page.
We can't save this record because the “Send Welcome Email to new Facebool Leads” process failed. Give your Salesforce admin these details. We were unable to process the email template. Error Message: core.email.template.TemplateRenderingException: We don't recognize the field prefix Recipient. Associate a record that matches the prefix or update the template to remove the merge field from the body, subject, or letterhead. Error ID: 1475201610-63539 (-1854030112)

Basically it complains about the prefix 'Recepient' in the field. When sending the email manually based on the template it does work correctly. Also when I'm deleting the field from the template the email is sent. Changing the prefix to Lead also didn't solve the issue.

Any hint is highly appreciated.