If the custom notification doesn't have parser the notification is not displayed.
Prereq: remove the parser for review notification.
In ./vendor/ezsystems/flex-workflow/bundle/Resources/public/js/views/fw-notificationspopupview.js remove line 62:
Steps to reproduce:
1. Send content to review.
2. Wait for notification.
3. Open the notification popup.
Actual: There are information in console about missing parser and the notification is not displayed.
Expected: There are information in console about missing parser, deprecated logs and the notification is displayed in old way.