I currently have 2 workflows to build my back and my front on my project linked to my main branch.
This workflow works perfectly.

I therefore duplicated this workflow to carry out the same process but for a second pre-prod branch and thus carry out the build on my pre-prod server.

These new workflows never trigger despite my multiple attempts.

Here is the current workflow that works for my main branch:

name: Check update and deploy backend
on:
  pull_request:
    branches:
      - main
    types:
      [closed]
    paths:
      - 'back/**'

jobs:
  changed_files:
    if: ${{ github.event.pull_request.merged }}
    name: Deploy backend
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 2

      - name: Set up Node.js
        uses: actions/setup-node@v4
        with:
          node-version: '20.x'

      - name: Install dependencies
        run: 
          cd back && npm install
// and other jobs tasks

So I made the necessary modifications to achieve the same thing but when merging a branch onto my pre-prod branch:

name: Check update and deploy preprod backend
on:
  pull_request:
    branches:
      - pre-prod
    types:
      [closed]
    paths:
      - 'back/**'

jobs:
  changed_files:
    if: ${{ github.event.pull_request.merged }}
    name: Deploy backend
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 2

      - name: Set up Node.js
        uses: actions/setup-node@v4
        with:
          node-version: '20.x'

      - name: Install dependencies
        run: 
          cd back && npm install
// and other jobs tasks

My .github/workflows folder is at the root of the project in the main, pre-prod branch as well as in that of my feature-branch which must be merge from my fork.

This workflow is therefore never triggered after a commit, then pull request to remote/pre-prod then merge from this PR.