Word conversion from pages is corrupted
Something you could try is installing LibreOffice and opening the Word formatted document there and immediately resaving it. I've found that LibreOffice is much more forgiving and saving a document through it will result in a file that Word will be able to open without issue. Same with Excel formatted spreadsheets that refuse to open in Excel.

I usually end up installing LibreOffice on every machine I use specifically for this reason.