Socket.io reconnects after a button is clicked

So I have a node.js / socket.io multiplayer game. And the socket.id get's redefined on the button click.

The .js Script function of the button:

var continueBtn = document.getElementById("continueBtn");
    var usernameInput = document.getElementById("usernameInput");
    continueBtn.onclick = function(){
        if(usernameInput.value != ""){
            socket.emit('playerCreated',{
                name:usernameInput.value
            });
        } else {
            alert("Username can't be empty");
        }      
    }

The socket.id is set to a random number when a new player connects:

io.sockets.on('connection', function(socket){
    console.log('socket connection '+socket.id);
    socket.id = Math.random();
//...
}

The responding code to the "playerCreated" socket.emit:

socket.on('playerCreated',function(data){
        var player = Player(socket.id, data.name);
        SOCKET_LIST[socket.id] = socket;
        PLAYER_LIST[socket.id] = player
        console.log("Player created with name: \""+PLAYER_LIST[socket.id].name+"\"");
    });

Why does my socket.id get reset to a new random number when I create a new player?

++Edit++

I am also running two intervals on the server side:

var isInitialized = false;
setInterval(function(){

    if(!isEmpty(PLAYER_LIST)){
        var pack = [];
        for(var i in PLAYER_LIST){
            var player = PLAYER_LIST[i];
            player.x++;
            player.y++;
            pack.push({
                x:player.x,
                y:player.y
            });
        }
        for(var i in SOCKET_LIST){
            var socket = SOCKET_LIST[i];
            if(!isInitialized){
                if(PLAYER_LIST[socket.id].room === ""){
                    socket.emit("initialization", {initGrid: initPack.grid})
                }else{
                    socket.to(PLAYER_LIST[socket.id].room).emit("initialization", {initGrid: initPack.grid})
                }
                isInitialized = true;
                
            }
            if(PLAYER_LIST[socket.id].room === ""){
                socket.emit("update", {initGrid: initPack.grid})
                socket.emit("playerlist", PLAYER_LIST)
            }else{
                socket.to(PLAYER_LIST[socket.id].room).emit("update", {initGrid: initPack.grid})
            }
            
        }
        
    }
    
},1000/25);

setInterval(() => {
    for(var i in SOCKET_LIST){
        var socket = SOCKET_LIST[i];
        console.log(PLAYER_LIST[socket.id].name +" ### Team: "+PLAYER_LIST[socket.id].team+" ### Role: "+PLAYER_LIST[socket.id].role);

    }
}, 2500);