Unfortunately, sometimes this does tend to happen, but sometimes there is a reason.
If the claim was "similar" to another claim, they may have merged the two together or consider it pyramiding.
Sometimes they just forget a claim. Yes, this does happen. The claim may also have been submitted, but the C&P doc simply fails to report on it. Yes, they can screw this up too. If a claim is missed, it is still considered an open claim.
Because you filed hardship, if you qualified they should have hopefully jumped on it sooner than this. I'm not very familiar with hardship requests, so hopefully someone more knowledgeable will help out. I just wanted to let you know the VA really does miss things sometimes.