I set the system to offline and checked in a logged out browser
upgraded to 18.2 from 18.1 following the instructions (backup files, backup database, copy new files over old ones)
I logged in again but there was no "Upgrading page" displayed. Just a message to delete the setup folder.

Issue : Tickets lists don't show

Symptoms : after logging in to the portal I see everything as far as the menu bar with open/my tickets/closed/search/new ticket. Nothing beyond that no page footer etc.
If I click the admin menu everything appears to be fine, full pages delivered etc. and it reports 1.18.2 in the system page

Dasboard / Information page shows :
Server Information
osTicket Version v1.18.2 (53339df) — Up to date
Web Server Software Apache/2.4.52
MySQL Version 10.6.21
PHP Version 8.4.3
PHP Extensions
gdlib Used for image manipulation and PDF printing
iconv Useful for email processing
imap Useful for email processing
ctype Required for email fetching
xml XML API
xml-dom Used for HTML email processing
json Improves performance creating and processing JSON
mbstring Highly recommended for non western european language content
phar Highly recommended for plugins and language packs
intl Highly recommended for non western european language content
fileinfo Used to detect file types for uploads
zip Used for ticket and task exporting
APCu Improves overall performance
Zend Opcache Improves overall performance

PHP Settings
cgi.fix_pathinfo "1" is recommended if AJAX is not working
date.timezone UTC
Database Information and Usage
Schema osticket202211 (localhost)
Schema Signature 5fb92bef17f3b603659e024c01cc7a59
Space Used 1643.33 MiB
Space for Attachments 617.52 MiB
Timezone GMT (Interpreted as Europe/London)

Installed Language Packs
English (United States)
en_US — include/i18n/en_US

Plugins installed are:
Plugin Name (instances) Version Status Date Installed
Help Desk Audit (1) 0.1 Enabled 2022/11/07 21:24
LDAP Authentication and Lookup (1) 0.6.2 Enabled 2022/11/07 22:17
Oauth2 Client (7) 0.6 Enabled 2022/11/07 21:24
Password Management Policies (2) 0.1 Disabled 2022/11/07 21:24
Two Factor Authenticator (1) 0.3 Enabled 2022/11/07 21:24

Errors
Nothing on screen or in the browser console
There are no errors showing in the system logs.
Error message in apache2/error.log:
...PHP Fatal error: Allowed memory size of 536870912 bytes exhausted (tried to allocate 8192 bytes) in /var/www/help/include/class.orm.php

It was originally set to 256M. For 1.18.1 it was php 8.2 and memory_size was set to 256M
I've now set it to php8.4 and 512M of memory and restarted both apache and php8.4 fpm and confirmed with phpinfo. but i still get the same error.

With so few errors its not giving me much to go on

Any suggestions appreciated