Explanation:
Box 1: Yes
User1 is in Group1.
User1 is in OU1.
Note:
The filter is for Group1 and OU1.
Box 2: No
User2 is in OU2.
User2 is in Group2.
Group2 is in OU1.
Group2 is a member of Group1.
Box 3: Yes
Group1 is in OU1.
Note: You can use multiple filtering options at the same time. For example, you can use OU- based filtering to only include objects in one OU. At the same time, you can use attribute-based filtering to filter the objects further. When you use multiple filtering methods, the filters use a logical "AND" between the filters.
Reference:
https://learn.microsoft.com/en-us/entra/identity/hybrid/connect/how-to-connect-sync-configure- filtering