Hey Linc it happens when I click on the PDF button. After a while, the pull down menu appears with the respective options, so it happens before the process of saving the file (selecting file type, folder, etc, and save).
Hope this helps you to find something. I have not tried deleting the MacPro from the Sharing Propierties in the MBP and see if the MBP keeps seeking for that server. Will try that later and update here.
Thanks for taking the time, man!