I have a template for one email account with a specific font setting for email text. This worked fine in v. 10. In 11 beta , eM Client shows both existing emails (sent and received) and new emails in a different font.
Also, whatever font is in effect for the default account is the font 11 beta uses in creating a new mail, even if you change accounts to an account that uses a different font in its template.
And, when viewing an email in the reading pane using the account with a specific font set, a message received from someone in the same organization (who uses the same font) appears normal, but then the font displayed in that received message changes when I click reply.