After different approaches, I found the issue may just the connections with the bluetooth device and the socket. I created an escape char in the data transmission to know when the stream is complete from the bluetooth device. Below works as expected.

               var sb = StringBuilder()
               inputStream.read().let {
                    if (it.toChar().toString() == "#") {
                        mHandler.obtainMessage(
                            HandlerConstant.MESSAGE_READ,
                            sb.toString()
                        ).sendToTarget()
                        sb.clear()
                    } else {
                        sb.append(it.toChar())
                    }
                }

Thanks for the help. This link helped me land on this approach Android Bluetooth InputStream read in realtime