Moodle 4.3.3 (20240212)  on Debian 12 / Apache 2.4.57 / libapache2-mod-xsendfile 0.12-2 and config.php with:

$CFG->xsendfile = 'X-Sendfile';

$CFG->localrequestdir = $CFG->dataroot . '/temp/localrequestdir';

1.  In a course, create a database activity and add two fields, one «text» and one «file»
2. Add a new entry and upload a file
3.  Go to "Actions"->"Export entries", check «Include files in export» and click «Export entries»
4. Confirm
   1. empty tab - no file downloaded
   2. error in PHP logs:

      [Mon Mar 18 10:48:06.722110 2024] [:error] [pid xxxxxxx] (2)No such file or directory: [client ip:port] xsendfile: cannot open file: /var/www/xxxxxxxxxxxx/moodledata/temp/localrequestdir/jd2a/65f80dd6aec96/65f80dd6aee18/Exportfile.zip, referer: https://xxxxxxxxxxxxxxxxxxxx/mod/data/export.php?d=1&backto=https%3A%2F%2Fxxxxxxxxxxxxxxxxx%2Fmod%2Fdata%2Fview.php%3Fd%3D1

5. In mod/data/classes/local/exporter/entries_exporter.php in function create_zip_archive, replace

   $tmpdir = make_request_directory();

   
   with

   $tmpdir = make_temp_directory(uniqid('test'));

6. Confirm that database export worked as expected

If I understand correctly, make_request_directory create a directory which die with it's content at end of PHP request  (\core_shutdown_manager::register_function('remove_dir', [$dir]);), so, Apache/X-Sendfile haven't time to get the file

 
If correct, it's not specific to database activity, it could happen each time make_request_directory is used to download a file