invalid template_id (could not find in db)

Hello,
I have two projects that you can preview, but if you try to edit them, it displays - invalid template_id (could not find in db)
These projects used to work, and all other projects work OK.
We're using v3.15, although noticed this issue going back to v3.12.
We're using PHP 8.2, they may have worked OK on php 8.0.
The web files and permissions appear OK.
Do you have any suggestions on where to look or what to try, please.

Thank you

Can you try the set $development to true in config.php around line 43 and look for errors in the apache error log and the error_logs/debug.log file?

The issue was fixed.
Although we didn't appear to use symlinks, something odd was going on in our setup, and perhaps some folder redirections, which caused issues from Xerte v3.13.

Our path settings, set within the management area, were using /usr/local/projects/xerte/www/html/ , these were updated to /var/local/projects/xerte/www/html/ and then it started to work OK.