Many thanks for persisting and reporting. I’ve been able to reproduce the problem with the public 3.1 version of Hook. some hypotheses for the different results (where I could not reproduce it earlier)
- My prior test was with an internal (Hook 3.2) build;
- maybe I had inadvertently interacted with Hook such that it sent the add-bookmark request to Pinboard.
- maybe the timing of enabling the keyboard shortcut preference makes a difference.