I did this...
1. Created a new private board
2. Clicked "invite" on the menu
3. Clicked "invite people by sending them a link"
4. Copied the automatically generated link and sent it in an email
Unfortunately, I sent the link to the wrong person. Now I can't disable that link and I believe the unintended recipient still has access.
I did try to disable the link by clicking "invite", then "invite people by sending them a link", then choosing "disable link", but the link being disabled isn't the same one I sent originally. The original link still works