Hello,
This happens because you excluded security principal Self from the activity scope of the Blind User role. The security principal Self also includes all groups a user is a member of.
To fix your problem you can do the following:
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Create a new Security Role.
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Add Deny Read Groups permission to this role.
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Assign this role to Everyone over the groups that you what to hide.
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Exclude the users that you want to allow to view these groups from the activity scope.
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We are considering changing this behaviour, and probably in the next version, the security principal Self will be treated as the self user account only.