As explicitly stated in the Permanence scroll text, which can be found in the "Item and Scroll Helper":
"Permanent Duration automatically grants a Spirit Lock Ritual when cast. This additional Spirit Lock does not count as a separate Ritual on the item, but is inherent in the Permanent Duration Ritual itself and may not be removed without also removing the Permanent Duration Ritual."
If your spirit cannot accept another Ritual, a Spirit Link cannot Link to you.
-Bryan Gregory
ARC