Please explain: unknown "fellow" joins meet.jitsi room

I’m a new user of meet.jitsi. I created an unsecured room and prior to sharing the link to the room, I had the room sitting open on my laptop. I was doing some other chores when I noticed some unknown “Jitsi Fellow” had joined the session (no video or audio). They hung around for 30 seconds then disconnected.

How is this possible? Given that my room name was 3 random dictionary words, it seems unlikely for someone to guess.

We call this ghost participant, in normal circumstances this can happen if you network goes down and you reload the page. This is actually your previous participant with no connection (the connection is bosh and has timeout of 60 seconds).
The last few days we had coping with a lot of traffic and very big load on our infrastructure and a reload is very possible to had happen while you were alone in the room.