[D7] Wrong variable substitution using t()

At the config screen, in my case admin/config/content/ckeditor/edit/Full, in fieldset 'CSS', the description under 'Editor CSS' is not complete. Line 966 of ckeditor.admin.inc is looking for non-existing substitutions of variables '!title_define_css' and '!title_ckeditor_default'.

    $form['css']['css_mode'] = array(
        '#type' => 'select',
        '#title' => t('Editor CSS'),
        '#default_value' => !empty($profile->settings['css_mode']) ? $profile->settings['css_mode'] : 'theme',
        '#options' => array(
            'theme' => t('Use theme CSS'),
            'self' => t('Define CSS'),
            'none' => t('CKEditor default')
        ),
        '#description' => t(
            'Defines the CSS to be used in the editor area.!title_theme_css – load the !style_css file from the current site theme.!define_css – enter the CSS file path below.!ckeditor_default – use the default editor CSS.',
            array(
                '!title_theme_css' => '<br /><strong>' . t('Use theme CSS') . '</strong>',
                '!title_define_css' => '<br /><strong>' . t('Define CSS') . '</strong>',
                '!title_ckeditor_default' => '<br /><strong>' . t('CKEditor default') . '</strong>',
                '!style_css' => 'style.css'
            )
        )
    );

The description string should be: 'Defines the CSS to be used in the editor area.!title_theme_css – load the !style_css file from the current site theme.!title_define_css – enter the CSS file path below.!title_ckeditor_default – use the default editor CSS.'