Under Call Recording Reports>Settings, the "Remove zero duration files" option when set to Yes - it isn't removing zero duration files on an ongoing basis. It only removes them once when you click "Yes" and then save again. It should be removing all zero duration files on an automatic basis.
Tooltip says "Remove files with zero duration. Also, this option won't display zero duration files anymore. Once this option is selected, all files are deleted from the disk. No recovery possible!"
It's not doing the ongoing clearing of zero duration files as it should, please fix it otherwise there are thousands of zero duration files that should be getting automatically cleared with this option set to yes.