Skipped "1" because it is not a valid MIME type

Question

I'm using react-dropzone to upload excel file data. my dropzone code is below:

const { getRootProps, getInputProps, isDragActive } = useDropzone({
        onDrop: handleDrop,
        accept: '.xls, .xlsx',
        multiple: false,
    });

It works fine but there are getting lots of warnings in the console. if anyone had leads please help me with that.

expecting bug free code and explanations