AD import rule may add only some computers to a designated organizational group.
Problematic scenario: OU is excluded from AD import Computer rule. Computers removed correctly. Add OU back into selection and only some part of computers appear in org.group.
Problem is caused when OU is excluded from import. While computers are removed from the group accordingly, ResourceUpdateSummary table is not properly updated, causing problem with future imports.
The issue was originated by "spResourceUpdateSummaryFullUpdateBulk" stored procedure with a faulty logic, which leads to the (totally invisible) corruption of ResourceUpdateSummary table integrity.
This issue has been resolved in 8.0 HF2 - See release notes for more information DOC9343
For those with ITMS 7.6 HF7, please refer to Pointfix attached to article INFO3459.
You can also use the attached stored procedures and manually add/update the stored procedures with the fix:
Very rarely the steps above still don't resolve the problem and it is necessary to manually edit the database and delete the affected records from resourceupdatesummary table for both the Inv_OU_Membership and Inv_Global_Active_Directory_Details.