NoMethodError: undefined method `payload' for {:message=>"Ensure the project has issues.", :status=>:error}:Hash

https://sentry.gitlab.net/gitlab/gitlabcom/issues/4037939/?referrer=gitlab_plugin

NoMethodError: undefined method `payload' for {:message=>"Ensure the project has issues.", :status=>:error}:Hash
  app/controllers/concerns/web_hooks/hook_execution_notice.rb:8:in `set_hook_execution_notice'
    http_status = result.payload[:http_status]
  app/controllers/application_controller.rb:533:in `set_current_admin'
    return yield unless Gitlab::CurrentSettings.admin_mode
  lib/gitlab/session.rb:11:in `with_session'
    yield
  app/controllers/application_controller.rb:524:in `set_session_storage'
    Gitlab::Session.with_session(session, &block)
  lib/gitlab/i18n.rb:107:in `with_locale'
    yield
...
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Prompted by this internal customer report. 2 dozen others seem affected as well, according to the Sentry data.

For the reporting user, specifically the Issues Events triggers this 500 error, but for:

some test we get a 200 response and everything shows up in our external logs

They confirmed that the project "always had [GitLab] issues" (not problems).