Why some GitHub actions stopped executing?

I have 3 workflows, that validate a directory/file each one (web, server, dockers).

Everything worked fine, until I added a "labeler" workflows to label PRs with web/server/docker labels.

The labeler workflow:

name: "Pull Request Labeler"
on:
  pull_request_target:
    types: [opened, synchronize, reopened, labeled, unlabeled]

jobs:
  labeler:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/labeler@v3
        with:
          repo-token: "${{ secrets.GITHUB_TOKEN }}"

One of the workflows that stopped working:

name: Server validation

on:
  push:
    branches: [master]
    paths:
      - ./server
      - .github/workflows/server-validation.yml
  pull_request:
    branches: [master]
    paths:
      - ./server
      - .github/workflows/server-validation.yml

jobs:
  validation:
    name: Server validation
# ...

Is there anything wrong? I didn't change the directory structure, the master branch name, or the workflow file.

This is the repository, where only the "labeler" workflow is executing: https://github.com/ivancea/autostocklist/actions

It has been happened since the last week, so I'm discarding any GitHub temporary problem.