Legal Question in Civil Litigation in California

You are required to plead all causes of action arising out of any single incident or set of circumstances at one time. You cannot file a new lawsuit on a new legal theory after losing on your first legal theory. In the situation you described, however, it may be a little more complicated. If you requested documents under one set of laws, were rejected, sued, and the rejection was upheld, and you later found that you could ask for the documents under a new or different law, and asked again under that law and were rejected again, you might be allowed to bring a second suit on the second rejection. Without spending a lot of time in the law books I can't say for sure which way that would go, and of course doing hours of legal research is beyond the scope of a free internet Q&A.

I would say that if it is the same parties, the second lawsuit would be barred under the doctrine of res judicata. The fact that you misconceived the legal theory under which you sought relief in the first lawsuit, does not give you a second bite at the apple.