RAK8212/BG96 tcp close socket anomaly

Ahh, ok. Can you try this code for send please?

  send: function(sckt, data) {
    if (busy || at.isBusy() || socks[sckt]=="Wait") return 0;
    if (!socks[sckt]) return -1; // error - close it
    busy = true;
    at.register('> ', function(l) {
      at.unregister('> ');
      at.write(data);
      return l.substr(2);
    });
    at.cmd(`AT+QISEND=${sckt},${data.length}­\r\n`), 10000, function cb(d) {
      dbg("AT+QISEND response "+JSON.stringify(d));
      if (d=="") return cb; // handle \r\n before >
      if (d=="SEND OK") busy = false;
      else {
        // probably d=="SEND FAIL"
        at.unregister('> ');
        socks[sckt] = null; // force socket close
      }
    });
    return data.length;
  }

If that works, I'd be interested whether it works without the if (d=="") as well...