Hmm. The sword can do that sort of damage. Cut away memories, or emotions you have towards memories or people.

But that should take a concerted effort. The other person I gave the sword to cut a bond he didn't want - he focused on solely the bond. He's still, uh, vividly angry about how that bond happened, so that seems a reasonable indicator only the bond was cut, yeah?

I will say he was trained as a Jedi. I don't know how that might have factored into the results.