I found some users changed their AD username, and then lots of workflows which has an notification (i picked ad user as recipient ) ended unexpectedly.
From the workflow history i can see , it will still try to find their e-mail address by their old user name account.
Failed to send notification. Cannot get the full name or e-mail address of user "i:0#.w|domain\oldusername".
I checked the SharePoint user profile service, it's updated.
it seems workflow has own cache? it will not updating self? should i republish all workflows, but we still have lots of running workflows. then How to fix this issue?