The Indent feature in the Rich Text editor loses its formatting when clicked on "Wiki Markup", "Preview" and "Save"

When the Indent icon is clicked to indent a particular text and then the "Wiki Markup" , "Preview" or "Save" buttons are clicked, the text indentation is lost. Instead the indented text is appended to the line above and a single line of text is generated. For example, the text below when typed in the "Rich Text" editor using the Indent button:

Header
A line of indented text.

appears as shown below, when saved, previewed or when switched to the "Wiki Markup" mode:

HeaderA line of indented text.