Update SC9.6.000 - fclose() error

Having had the living hell with the 9.5.X updates, I have moved to 9.6.000. The manual update went cleanly, it performed its own updates on first login and all seemed OK until the final install test - let SC build one of its own demo/sample applications. This failed with an error

             "fclose() expects parameter 1 to be resource, bool given"

What could be going on here? Honestly, I am tired of the increasing errors with a simple install or their own update facility. I can’t fix it as the .php with the error is protected. There are no errors logged in /var/log/httpd/error_log.
File security context, permissions, ownership and group are correct. Same error with or without SELinux active and with (ridiculous) 777 permissions for everything.
Your feedback is welcomed.

Hi @Sean_H

Just a few questions?

  1. What OS are you using for development environment?
  2. What PHP version?
  3. What Webserver?

CentOS 7, PHP 7.3, Apache
SC Diagnose claims all is well