the lighthouse report tracker action will run only when pull requests are open, synchronized or reopened.
the github issue tracking your lighthouse report logs will be updated when a pull request is merged, meaning on subsequent pull requests, the most up to date lighthouse report log will be based on the previous pull request's lighthouse report.
note : if you have other actions set up where pull requests are open as a result of the action(i.e. dependabot, imgbot etc.), make sure to prevent your lighthouse ci workflow from running(unless you want it to be tracked) because when a pull request is merged, the lighthouse report tracker action will update the github issue light house report log used for subsequent pull requests.
ex)
// edit your workflow based on bots