Hi Igor, I believe the problem is in:
(defun pcomplete/org-mode/searchhead () ... ;; When completing a bracketed link, i.e., "[[*", argument ;; starts at the star, so remove this character. (substring pcomplete-stub 1)))) <-- trailing ]] not removed! Changing the last line to (substring pcomplete-stub 1 -2) fixes it in my example. I don't know if one is supposed to do [[*prefix<c-a-p>]] or [[*prefix<c-a-p> as is implied by the code, but better to support both, specially considering electric pairs, don't you think? Best regards, Carlos