"I show that 2 invitations were sent to that email address for that wiki. One of them was accepted by your account Leprof. This happens quite a bit, especially in a situation where computers might be shared, like in a classroom.

It does not mean that that person now has access to your account. Your account is safe. All that it means is that the invitation is now invalid since it's been used.

The person should accept the other invitation that was sent to them."