Similar effect can happen the other way around and in fact I have seen that more often (albeit mostly 10 years ago): - create DOCX with change tracking in Word

Similar effect can happen the other way around and in fact I have seen that more often (albeit mostly 10 years ago): - create DOCX with change tracking in Word - edit that in LibreOffice and save multiple times - open it in Word modify something and save - Word cannot load that file. Loading and saving in LibreOffice fixes that. All cases I have seen involved change tracking, which is probably not that surprising as the internal representation of change tracking in DOCX is totally brain damaged (even more than the rest of that "dump RTF and random crap as XML" format).