Editing PR first comment or title does not trigger a workflow

Coming from actions/typescript-action327.

I’m trying to write an action that will check/watch the first comment of PRs. Each time the comment is edited/updated, the workflow should be executed. I tried with the following workflow:

name: 'Self-labelling'
on: [pull_request, issues, issue_comment]
jobs:
  build:
    strategy:
      fail-fast: false
    runs-on: ubuntu-latest
    steps:
    - uses: 1138-4EB/actions@tip

I found that it is executed when I open a PR, respond to a PR (new comment), open an issue, respond to an issue, edit the body of the first comment of an issue, etc. However, it does not work neither when editing the first comment of a PR nor when editing the title of a PR. Therefore, it seems that the only option to trigger the workflow after the PR is created is to synchronize it again. I would expect that any of these actions would trigger pull_request edited, issue_comment edited or issues edited.

Can you give the following a shot and see if it works?

https://github.com/actions/typescript-action/issues/27#issuecomment-532639421