Sending multiple data between the two NodeMCU using Serial communication
You should provide a string or char array into the
  JsonObject&amp; root = jsonBuffer.parseObject(s);

The s variable is an object here for SoftwareSerial library.
You firstly need to read the serial like
while(s.available()){

String r = s.readString();
JsonObject&amp; root = jsonBuffer.parseObject(r);
}

Here r will be a raw json array and json object will parse it.
And it will be good if you upload your output to understand and see what is really going on
Update:
Using UART with 115200 baudrate without delay and with jumper cables may cause the miss of the characters.
The other issue is, maybe this is happenning because of monitoring the Serial port at the same time. Maybe you can debug it with just looking the digital pins which you are controlling to understand your code is working fine or not.You can
Or you can try I2c communication which is synchronous and more reliable and faster instead of UART.
Actually, SoftwareSerial library is a bit slower than the actual serial port.