Getting ‘undefined’ for a variable in Express Js Server, but it is working for another variable with same code

Here is my server.js:

const express = require('express');
const app = express();
const fs = require('fs');
const bodyParser = require('body-parser');

app.set('view engine', 'ejs')

app.use(express.static('public'));
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());

// Alternatively, read the combinations from another route
const combinations = require('./routes/combinations');

app.get("/", (req, res) => {
    res.render('index')
})

app.get("/contact", (req, res) => {
  res.render('contact')
})

app.post('/like', (req, res) => {
  const votes = req.body.votes;
  const Comb_Id = req.body.Comb_Id;
  console.log(votes)
  console.log(Comb_Id)
  const matchedId = combinations.find(c => c.Id === Comb_Id);
  console.log(matchedId)
  if(matchedId) {
    matchedId.vote = votes;
  }
  else {
    console.log("didn't work");
  }
});

app.post('/dislike', (req, res) => {
  const votes = req.body.votes;
  const Comb_Id = req.body.Comb_Id;
  const matchedId = combinations.find(c => c.Id === Comb_Id);
  
  if(matchedId) {
    matchedId.vote = votes;
  }
  else {
    console.log("didn't work");
  }
});

// Set up the endpoint to handle form submissions
app.post('/', (req, res) => {
  const dropdown1 = req.body.dropdown1;
  const dropdown2 = req.body.dropdown2;
  const dropdown3 = req.body.dropdown3;
  const dropdown4 = req.body.dropdown4;
  
  // Find the combination in the file or from the route that matches the user's selection
  const matchedCombination = combinations.find(c => c.dropdown1 === dropdown1 && c.dropdown2 === dropdown2 && c.dropdown3 === dropdown3 && c.dropdown4 === dropdown4);
 
  if (matchedCombination) {
    // If there's a match, send the corresponding result
    var output = JSON.stringify(matchedCombination.result);
    var user_votes = JSON.stringify(matchedCombination.vote);
    var comb_Id = JSON.stringify(matchedCombination.Id);
    //res.json({ result: matchedCombination.result });
    console.log(output)
    console.log(user_votes)
    console.log(comb_Id)
    res.render('index2', { story: output, dropdown1, dropdown2, dropdown3, dropdown4, scrollToResult: true, votes:user_votes, Id:comb_Id });
  } else {
    // If there's no match, send an error message
    //res.status(400).json({ error: 'Invalid combination' });
    res.status(400).render('index2', { story: 'Invalid combination', dropdown1, dropdown2, dropdown3, dropdown4, scrollToResult: true, votes:user_votes, Id:comb_Id });
  }
});


app.listen(8000, () => {
  console.log('Server started on port 8000');
}); 

Here is combinations.js file:

const combinations = [
  
  { dropdown1: 'A', dropdown2: 'F', dropdown3: 'L', result:1, Id:100, vote:0},
  { dropdown1: 'A', dropdown2: 'F', dropdown3: 'M', result:2, Id:200, vote:0},
  { dropdown1: 'A', dropdown2: 'F', dropdown3: 'N', result:3},
  { dropdown1: 'A', dropdown2: 'F', dropdown3: 'O', result:5}
]
module.exports = combinations; 

in the server.js file, I am getting the proper result for “matchedCombination” but I am getting undefined for “matchedId” and I am not finding any solution or the issue here.

some more details: I am calling the matchedcombination variable to get the value from combinations.js when the user submits a dropdown form. This flow is working as expected and I am getting the results.

When user has the results in front of him, he can either like or dislike it. To do this, I have added an ID field in the combinations.js. When user submits the dropdown to get the output, I pass this Id to my HTML. When user clicks on like or dislike button, this ID is passed back to the server from the HTML.
I did this to identify the combination of dropdown options the user selected. Using this ID now I want to fetch and update the vote field in combinations.js. That is the plan.