Checkboxradio not working in WordPress

[Bill Farmer]

I have a new virgin install of WordPress - 4.9.8. It does include jQuery, but not the latest jQuery-UI. I am developing a plugin using the checkboxradio widget, so I have used the latest version of jQuery-UI as part of the plugin. After using the refresh function the state of the radio button is updated correctly, but the label text disappears. On looking at the HTML in an inspector, the label text has been replaced by a number of blanks. This happens on all three themes included with WordPress. It does not happen on a plain vanilla web page not in WordPress. I have looked at the styles in an inspector and at the checkboxradio code and I can't see why it doesn't work. I can't produce a test case because it only happens inside a WordPress site.

[Bill Farmer]

This HTML is from a plain vanilla web site which works fine...

<label for="radio-1" id="label-1" class="ui-checkboxradio-label ui-corner-all ui-button ui-widget ui-checkboxradio-radio-label"><span class="ui-checkboxradio-icon ui-corner-all ui-icon ui-icon-background ui-icon-blank"></span><span class="ui-checkboxradio-icon-space"> </span>Images</label>

This HTML is from a wordpress site, note the newline and blanks in the label

{{{<label for="question-radio-1" class="question-label ui-checkboxradio-label ui-corner-all ui-button ui-widget ui-checkboxradio-radio-label" id="question-label-1"><span class="ui-checkboxradio-icon ui-corner-all ui-icon ui-icon-background ui-icon-blank"></span><span class="ui-checkboxradio-icon-space"> </span>

</label>}}}

The newline which breaks the wiki formatting appears to be in the HTML.