According to section 12.6 of the 1.2.0 NHibernate docs "Version properties, identifiers and associations are ignored". And this is the behavior that I observe.

However I see this as dangerous because if you use this feature and consume an object with one of the ignored properties set this portion of the filter is simply ignored. Would it not be better to throw an exception in this case because the filtering only takes into account a portion of the consumed object and I do not believe that this is clearly communicated to the developer.

Submit a feature request and I will consider it but I don't promise anything.