Total agree that recreation.gov should have let you know. What if you hadn't checked with the forest service? No way you would know your reservation was invalid.
Sadly, I don't have much faith in recreation.gov. Besides this, I've seen many other errors from them in the past incl. allowing booking of sites that didn't exist (happened to us once...the campground had closed several sites, but the recreation.gov system still showed them as valid) and wrong information (e.g. hookups which were not there or visa versa even). I know a lot of the info depends on 2-way communication so I guess part of the blame falls on the forest service for not including recreation.gov in their notices (at least I assume that's part of the problem). Still, it's frustrating either way.
On another note, sure hope that hot/dry spell doesn't cause anymore forest fires. It's dangerous out there. Keep safe all.