I have the 1.8 version of Publisher and the tel: XXXXXXXX seems to be working fine now.
I will admit, I've had issues with this in the past. And today I was again searching for an answer but I couldn't find one.
Some trial and error resulted in the following process that works for my exported .pdfs. I hope it works for you as well!
I select the shape, right click the mouse, select "Interactive", select "Edit Hyperlink".
Select URL. I typed in tel: the telephone number. I placed a space between the colon and the phone number. Hit OK
Follow the same process as above for a second time except instead of selecting "Edit Hyperlink", select "Go to Hyperlink Target" and select the phone type.
Good luck
Rich