User signature is not inserted into emails on Email-to-Case

Issue

Enabling the "Place User Signatures before Email Threads" check box in the Email-to-Case settings, does not insert the User signature in the emails sent from the Emails related section on the Case detail page. 

The setting 'Place User Signatures before Email Threads' adds the User signature after the reply, but before the email thread. If this setting isn’t selected, the User signature is placed at the bottom of the email thread.
 

Note: Previously User signatures in emails sent from Case Feed were always appended at the bottom of outgoing email threads. But now we can insert the user signature so it appears after the support agent’s reply, but before the email thread.