The Compose a text page does not use the HTMLArea editor, it is just a text editor without any need for formatting, ergo, no HTMLArea editor, just plain text editor.
You can replace the editor using ftp, that is, delete the existing code from lib/editor/htmleditor and replace it with the same code from your local development. Test it, if that does not work then do the same with the Admin folder. That tends to fix the issue - but not always.