I read 1516.1.2010 standard and it seems to me that correct behaviour would be to send object removal message even when federate is not anymore subscribed IF federate did get discovery of the object (while being subscribed). However I am not completely sure if I understand this correctly. The part that talks about unsubscribe does not mention anything about this case, but "Remove Object Instance service" part does not talk about subscriptions but instead says that federates that knows about objects should here about removal.

Also I am not sure if HLA 1.3 should work similarly like 1516.1.2010. I don't have full 1.3 documentation.

Fixing this like standard suggest is probably not trivial as RTIG does not keep book on who knows about objects.

One solution would be send object removal message to every federate in every case and let RTIA to just ignore objects it does not know about.

My earlier though about clearing objects on unsubscribe seem wrong according to standard.