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In Microsoft Purview, when multiple alert policies trigger alerts, duplicate alerts within a short period (typically 5 minutes) may be suppressed to avoid redundancy.

Step-by-step Analysis:

● Policy1 at 10:00:04 is ignored because Policy1 already triggered at 10:00:00, and it's within 5 minutes.

● Policy2 at 10:00:31 is ignored because Policy2 already triggered at 10:00:03, and it's within 5 minutes.

● Policy1 at 10:01:01 is a new alert because it's over 1 minute after the previous Policy1 alert.

● Policy1 at 10:04:45 is a new alert because it's over 3 minutes after the previous Policy1 alert.