Socket closing without prompt

Support plan

is this issue currently blocking your project? (yes/no): no
is this issue affecting a production system? (yes/no): yes

Context

node version: 16.0
module version: 12.0.4
environment (e.g. node, browser, native): browser (and node)
used with (e.g. hapi application, another framework, standalone, ...): hapi application
any other relevant information:

How can we help?

Some users in production are being unsubscribe from the socket without us really knowing why. Their internet access is supposedly stable... I feel I am missing some cases of automatic unsubscribe so I must ask : what are the different cases where the socket might trigger the onUnsubscribe function ?

Here are the different declarations:

/**CLIENT CODE connection **/
return this.socketClient.connect({
    reconnect: true,    //whether the client should try to reconnect
    delay: 2000,        //time in milliseconds to wait between each reconnection attempt, cumulative
    maxDelay: 15000,    //the maximum delay time in milliseconds between reconnections
    retries: 10     //number of reconnection attempts
})
/** SERVER REGISTER **/
await server.register(
  {
    plugin: Nes,
    options: {
      heartbeat: {
        interval: 15000,
        timeout: 5000
      },
      auth: false
    }
  },
  {
    routes: process.env.ROOT_PATH ? {
      prefix: ROOT_PATH
    } : {}
  }
);

this.serverFromRequest.subscription(this.subscribingPath , {
          onSubscribe: (socket, path, params)=>{
            /** SOME CODE that has nothing to do with network **/
            //Managing page reloading by clearing a timeout
            if (this.onUnsubscribeTimeout) {clearTimeout(this.onUnsubscribeTimeout)}
          },
          onUnsubscribe: (socket, path, params)=>{
           /** SOME CODE that has nothing to do with network **/
                const unloadTimeout =  15000;
                this.onUnsubscribeTimeout = setTimeout(()=>{

                 /** SOME CODE saying what should happen when socket is closed ( basically send message to client saying Chat is closed)
                }, unloadTimeout)
          }
        })

What do you think ? Is the fact maxDelay very closed to unloadTimeout could explain the issue ? Are my connect options not precise enough or too low ? Or the heartbeat maybe ?

What would be good production values according to your knowledge ? Regards and thank you for nes !

hapijs / nes