Computer2 fulfills the requirements of the group 2 membership rule. However one computer can be a member of just 1 ATP group, and priority is used for that purpose. This means both computers (Computer 1 & Computer 2) are on group1 because they both contain 1 and group 1 have the highest priority. "Specify the matching rule that determines which device group belongs to the group based on the device name, domain, tags, and OS platform. If a device is also matched to other groups, it's added only to the highest-ranked device group" https://docs.microsoft.com/en-us/windows/security/threat-protection/microsoft-defender-atp/machine-groups
Computer2 fulfills the requirements of the group 2 membership rule. However one computer can be a member of just 1 ATP group, and priority is used for that purpose. This means both computers (Computer 1 & Computer 2) are on group1 because they both contain 1 and group 1 have the highest priority. "Specify the matching rule that determines which device group belongs to the group based on the device name, domain, tags, and OS platform. If a device is also matched to other groups, it's added only to the highest-ranked device group" https://docs.microsoft.com/en-us/windows/security/threat-protection/microsoft-defender-atp/machine-groups