Just some info about the bug. We removed the restrictions completely, which was little bit too much, since it allowed you to build the blueprint on chunks that didn't have anything even generated, so the cause in this case is that the trees were created AFTER the blueprint was placed.
The new rule will be that blueprints are still limited, so you can only build on chunks that are charted, which reintroduces some kind of limitation, which indirectly also implies that they are fully generated already.