I think I found the problem. When I downloaded the backup of 2024-02-24, to overwrite the files 2024-02-26 the files were not all saved in the cache correctly by the JET system, 9 files were missing.
I just downloaded version 1.3.4 and discovered that there are files missing from the cache on my server. (apcu.php, memcache.php, xcache.php, memcached.php, file.php, driver.php, apc.php, redis.php). I replaced these in the cache folder and now it seems to work fine.
I still have the same warnings, Be careful Incorrect config.php file permissions, Warning Incorrect index.php file permissions
However, I have tried all the permissions, and I still get this message,... do you think I should be concerned about this?
Thank you everyone for your advice etc...