That was my reaction when I heard of the treaty, and I didn't even know what Astrum's claims were. but I did think to myself "Uh, why are they claiming ex-Caerwyn lands without consulting the people that defeated them?".
To build up a backed and ratified claim to use as a negotiation with the "real" claim holder. This was quite common, get other parties to recognise your claim in order to challenge other claims. It was helpful if those that recognised your claim also had a legitimate claim, but not needed.
