When using the Send Email core action in Salesforce Flow to send an email with a rich-text body. Switching between plain text and rich text in the template editor alters the HTML markup, resulting in incorrect rendering and formatting issues.
To avoid this, use a plain text template with HTML markup and select Rich-Text-Formatted Body as true in the Send Email action. This approach ensures the email body is formatted correctly. See the attached screenshots for reference.
Make sure to select Rich-Text-Formatted Body as true in the Send Email action
