Reference:
https://docs.microsoft.com/en-us/mem/intune/apps/apps-deploy
https://docs.microsoft.com/en-us/mem/intune/apps/apps-windows-10-app-deploy

Explanation

Box 1: No
Device1 is in Group2 as Name starts with Device and Tag contains Inventory.
However, the Group2 has alert severity low.
Box 2: No
Computer1 does not belong to either Group1 or Group2
Box 3: Yes
Device3 belongs to both Group1 and Group2.
Note: Understanding alert severity
Microsoft Defender Antivirus and Defender for Endpoint alert severities are different because they represent different scopes.
The Microsoft Defender Antivirus threat severity represents the absolute severity of the detected threat (malware), and is assigned based on the potential risk to the individual device, if infected.
Reference: https://docs.microsoft.com/en-us/microsoft-365/security/defender-endpoint/alerts-queue

References:
https://docs.microsoft.com/en-us/office365/securitycompliance/data-loss-prevention-policies This report also shows policy matches over time, like the policy matches report. However, the policy matches report shows matches at a rule level; for example, if an email matched three different rules, the policy matches report shows three different line items. By contrast, the incidents report shows matches at an item level; for example, if an email matched three different rules, the incidents report shows a single line item for that piece of content. Because the report counts are aggregated differently, the policy matches report is better for identifying matches with specific rules and fine tuning DLP policies. The incidents report is better for identifying specific pieces of content that are problematic for your DLP policies.