We are experiencing the same issue. All “strong” and “em” tags are converted to “b” and “i” in the stored/published content, not just temporarily in the WYSIWYG editor. HTML Tidy if off. A fix for this…
* Note - To input code samples, click the pencil icon (this will remove the WYSIWYG) then be sure to start and end code sections with @@@ (three '@' signs). For more information on textile markup, click here.