Hi! I'm sorry you've run into problems, unfortunately no-one has reported this before, so I'm afraid I don't have a quick answer for you. A couple of things that it might be worth trying:
* Reading items like your notebook, letters, etc. changes the state of what can be interacted with, it might be worth trying to reread anything you have in your inventory by right clicking on it to see if that unsticks something
* Try saving your game, quitting and reloading.
* If you have any window management extensions running on your Mac (like Magnet) try disabling them to see if they might be interacting with it in a strange way.
Unfortunately I'm away from home for the next week, so I won't be in a position to try and reproduce it for a little while, but if you can think of anything you did immediately before you noticed the problem it'd be very helpful to me when debugging it.
Thanks,
Mike