https://github.com/bitcoin/bitcoin/blob/d72758c3f6c34cd835f5de3efc230964f3b1ea56/src/torcontrol.cpp#L539

If a user is running Tor proxy outside localhost (perhaps on other host inside LAN or in containerised environment) , the automatic creation of onion services ends up creating an onion service listening to hardcored 127.0.0.1 address on the Tor proxy's host instead of the private address of the bitcoind – effectively running an empty onion service listening the Tor proxy's localhost.
{
    while (!interruptNet)
    {
        DisconnectNodes();
        NotifyNumConnectionsChanged();
        SocketHandler();
    }
}
void CConnman::WakeMessageHandler()
{
    {
        LOCK(mutexMsgProc);
        fMsgProcWake = true;
    }
    condMsgProc.notify_one();
}
#ifdef USE_UPNP
static CThreadInterrupt g_upnp_interrupt;
static std::thread g_upnp_thread;
static void ThreadMapPort()