We do not wrap the Store, Expression, imaging and mgnlVersion with MgnlAuditLoggingContentDecoratorSessionWrapper for now. We should make audit logging configurable per workspace.

When this issue is solved then remove from info.magnolia.repository.DefaultRepositoryManager

if ("imaging".equals(logicalWorkspaceName) || "Expressions".equals(logicalWorkspaceName) || "Store".equals(logicalWorkspaceName)) {
    // don't wrap imaging, expression and store into audit logging session
    return new MgnlVersioningSession(session);
}

and add imaging, Expression and Store into forbidden workspaces.

Concept: http://wiki.magnolia-cms.com/display/DEV/Concept+-+Move+AuditLog+from+Content+API+to+JCR+API