In the site settings -> workflow settings, the page only shows site workflows. When you click Workflow Health, the page shows all workflows include list workflows in the site.
If the Workflow Health page does not show all workflow, please go to Central administration -> Monitoring -> Job Definitions -> Check Bulk workflow task processing, Workflow, Workflow Auto Cleanup and Workflow Failover timer jobs are running.
If the issue persists, republish workflows and clear browser cache, compare the result.
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