Different errors when cleaning .xlsx files (Unsupported filetypes)

I tried cleaning all metadata from two different Excel files and got two different errors:

1. ERROR: In file /test/testfile.xlsx, element [trash]/0000.dat's format (None) isn't supported Shouldn't the .dat filetype be ignored anyway and not be in the supported files list.

2. ERROR: In file /test/testfile2.xlsx, element xl/sharedStrings.xml's format (application/xml) isn't supported Same with this .xml file. Since it isn't supported, shouldn't we just ignore it?

Thank you very much