Your CUtags.php?sce=dump shows$WX['date'] = '1/26/2018';
in mm/dd/yyyy format.
Your realtime.txt shows 26/01/18
which is dd/mm/yyyy format.
In Settings.php you have $SITE['WDdateMDY'] = true; // for WD date format of month/day/year. =false for day/month/year
so the PHP code is parsing the CUtags.php date ok.
In ajaxCUwx.js you have var showDateMDY = false; // set to false to show date as dd/mm/yy
so change that to var showDateMDY = true; // set to false to show date as dd/mm/yy
so the AJAX update will appear in mm/dd/yyyy format.
Note that only mm/dd/yyyy or dd/mm/yyyy formats are available with the AJAX script. Your Settings.php entries should match the selected format in order to not change date formats when the AJAX updates kick in for the page.