Currently the default name of an attachment is the name of the uploaded file, but truncated at the first period. So "Vendor invoice 2020.07.01.pdf" becomes "Vendor invoice 2020". But periods are legitimate constituents of file names. It makes sense to truncate the file-type extension, but that's the last period not the first one. If that can't happen, then don't truncate; just include the file-type extension.