@KevinCristiano only Divi so far -- I only suspect avada --- This plugin looks like the long term solution github.com/phdccltd/civicrm-539-wp-content-fix

@AlainB are you using Divi or Avada Theme?

@com1tech I suspect the permissions are the problem. Try making Classloader.php permissions 644.

Go to Administer/User and Permissions/Permissions (Access Control). The click on the top option Drupal/Wordpress/Joomla Access Control. Make sure anonymous users have "CiviCRM: access all custom data " checked

Have you double-checked that the permission "access all custom data" is On for end users?

You can refresh the page. Sometimes the upgrade will just timeout on one task, but a refresh will restart the timer. Also have you tried running the upgrade using CV on the commandline?

Are you getting an error or is it just spinning?

I am dealing with this as well. Are you finding it with only countries that the time is ahead?

How frequent are your Drupal Cron and CiviCRM Cron? AND is Clean Up Temporary Data turned on? Typically I see this error when the form is loaded but a session cache is cleared between the load and the submit. Temporary data only flushes data that is already old, but if the timestamps are not the same timezone as the site it can flush all current data. Check the logs for a form load/ cron run/ then submit failure pattern.