Emails are being sent with the incorrect "From:" email address.
The From email address set in the 'Send Email' action is being ignored (email@example.com). Instead, the email address in the Email Config used to authenticate the SMTP connection is always used (firstname.lastname@example.org).
The Email Config is using the SMTP Host: smtp.gmail.com
This may affect other email providers too.
When you use smtp.gmail.com to send email you authenticate with a Google account. This could be a standard Google Mail (GMail) account or a Google Apps account (also known as "Google Apps for Domains" or "Google Apps for Work").
The Email Config is configured to authenticate with the account's Primary email address, e.g. email@example.com.
In order to send mail using a different From: address, e.g. firstname.lastname@example.org, the authenticating account (email@example.com) needs to be configured to allow it to send email on behalf of ('Send mail as') the alias address, e.g. firstname.lastname@example.org.
If the primary email account (support@) is not authorised to send email as the From: address specified (technical.support@) then Gmail overwrites the From: address with the authenticating user email address (support@).
Google provides a knowledge article on how to send mail from a different address or alias:
If you need further assistance configuring this talk to your email administrator.