In some cases, the machines may need a further full reboot (specifically selecting 'restart', or holding Shift as Shut down is selected) to clear the alert, some cases may however require a few commands to be executed as an Administrator:
"C:\Program Files\ESET\ESET Security\ecmd" /registerav
"C:\Program Files\ESET\ESET Security\ecmd" /registeravsoft
shutdown -t 0 -f -r
Whilst these can be executed via a Run Command task (https://help.eset.com/protect_admin/90/en-US/client_tasks_run_command.html), because the third command is an immediate restart, we'd perhaps recommend only running these locally