Hi
Through graph API i see alerts for Defender portal but they does not appear in MS defender portal > Alerts
request :
https://graph.microsoft.com/v1.0/security/alerts?$filter=Severity eq 'Medium' and status eq 'newAlert'
our monitoring tool is based on this request so we have false alert ... 
in the dashboard > new alert or email & collab alert > nothing is shown (we have a filter on our monitoring tool for "Email sending limit exceeded"


thanks