Where do extra clients come from on the server?

Question

Socket.io

Hello, When I update the page, "Extra clients" appear. Why
do they simply accumulate
? For example: I go to the page - the server writes
"User connected" For some reason, it starts to accumulate these clients (Although, in fact, it should remove them when disconnected) In general, I ask for help (It would seem that I looked through everything, but I can’t find an answer) I write in Node js using socket.io