zc158a; PHP 8.2.15; PHP Memory Limit: 128M; DB MySQL 10.6.16-MariaDB-0ubuntu0.22.04.1

Note: This is no longer a problem on my site and the information is posted here for the search engines to find for future reference.

I could not edit one database record, found by chance, when checking on stock returned. The order details screen showed the order number and the remainder of the page was blank. No Zen Cart error logs were displayed.

I was getting the following error in my Apache logs
Code:
PHP Warning:  Undefined global variable $_SESSION in .../includes/extra_configures/enable_error_logging.php on line 84
with no zen cart error logs generated.

The problem was inadequate permissions on the logs folder. This was resolved when the folder permission was set to 774.
When the log files could be generated I had Zen Cart error logs complaining about duplicate defined names. These were due a legacy language file existing beside a 158 format lang file.

The duplicate defines errors does not occur on my Windows development machine or on my linux test machine.

When these redundant files were removed and no further zc log files were generated. The database record displayed correctly.