Thread:Project:Support desk/Some Files Not Typed Properly

I have an xls file to upload. In my environment, manually checking type with Fileinfo yields: However, when attempting to upload this same file MW 1.23.2 it yields:
 * $wgFileExtensions includes an entry for xls.
 * phpinfo output says PHP Fileinfo extension is loaded.
 * $wgLoadFileinfoExtension = true;

It's as though something else is being used for MIME type detection on files. Any idea what might cause this? (and how to fix it?). Thanks!