Session Timeout with shared hosting - warning
This discussion https://sendy.co/forum/discussion/16108/session-timeout outlines a problem (and a solution) for PHP sessions being unexpectedly garbage collected - resulting in a risk of edits being lost if they take longer than about twenty minutes.
I'd like to add to this but the discussion is closed.
If you're using shared hosting, it's possible that your PHP is set up to use a shared /tmp directory for session storage. This unfortunately means that if another PHP user garbage collects sessions, your sessions may be garbage collected using their settings. The default session garbage collection time is 24 minutes.
Make sure you change the PHP.INI file to use your own "tmp" directory rather than a shared /tmp directory so this doesn't happen to you...
(If the contents of an HTTP POST during re-authentication it would really help here).