Support

I recommend following the same advice I gave everyone else. The past 12 years there's been a warning in your Akeeba Backup Control Panel and when you're taking backups from the backend about using the default backup output directory. Please click that link to understand the implications and follow its advice to use a non-default backup output directory. This WILL remove the random string which is only appended IF you a. use a web accessible backup output directory (checked when you visit the Akeeba Backup Control Panel page and activate your backup profile from the dropdown) OR b. you use the default backup output directory.

You CAN change your backup output directory to overcome the built-in security protection. Ideally, this should be placed in a directory above your site's root. If this is not possible, please use a directory inside your site's root. A hard to guess name like "qebPw234wD_backups" is preferred to an easily guessable name like "backups". Do not place your backup output directory in a CMS system directory, such as Joomla's cache, tmp, media etc directories or WordPress' wp-content directory. After creating the backup output directory go to the Configuration page to change your backup output directory to it. This needs to be done once per backup profile. Remember to exclude your old backup output directory (default: administrator/components/com_akeeba/backup) from your backup to prevent backing up any existing backups which may still be in there.

When you next visit Akeeba Backup's Control Panel, Akeeba Backup will try to protect the backup output directory and check if your directory is accessible over the web. The test for whether the backup output directory is accessible over the web takes place when you visit Akeeba Backup's Control Panel page and activate the backup profile in question from the dropdown list. First, Akeeba Backup will place a .htaccess, web.config, index.html and index.html file if they are not already present. For this reason it's IMPERATIVE that your backup output directory is NOT the parent folder of a web accessible location. The check will then try to write a randomly named file in your backup output directory and access it over the web. This may create an entry in your server's error log. If this happens do not worry; it's normal and it means that everything is working correctly.
If the backup output directory is EITHER above the site's root (therefore by definition inaccessible over the web) OR positively identified as being inaccessible over the web THEN and only then Akeeba Backup will stop adding the -[RANDOM] suffix to the names of your backup archives.

That is to say, having an output directory above the site's root is NOT a requirement.

Even if you are using NginX, which does not understand .htaccess or web.config files, you CAN use Admin Tools' NginX Conf Maker and its Frontend Protection feature to block web access to all folders not explicitly allowed. If you follow the suggestions above your folder will not be in the default allowed list, therefore access to it over the web will be disallowed.

I wouldn't tell you to do something if I didn't know that it's possible to do it. I never ask you to do the impossible.