It may be that then dot files snuck in due to an ‘upgrade’ to the zipping software breaking something. In earlier verions they were excised…
Light has, I hope now been corrected.
1) What’s the version of Adobe Acrobat that you’re using?
2) Any PDF reader should be able to open the latest versions – build date is 06 May 14.
3) The whole topic is also available on the web.