In PHPocx 5.0 -> 6.5 the function createDocxAndDownload from Crate/CreateDocx.inc changed in that it is now possible to have .docx trailing the name.
In doing so the filesize and readfile functions now take the name of the file minus the trailing .docx as name instead of the whole path.
I would suggest that the function to remove the trailing .docx also includes the full path and use that in the functions above.
This way you still have controle over the temp save path of the file to generate.