Well, i really don't see it this way.
"Presumed innocent until found guilty" is meant to communicate that, from the perspective of the law, if we MUST make a presumption, that presumption is that the defendant is innocent unless we prove guilt beyond a reasonable doubt in a court of law.
However, even that simple description is flawed, after all, if the defendant is innocent, how can we justify imprisoning them for a trial in the meantime ?
But we can, of course, put a nail in the coffin of this usage with the case of OJ- if OJ was "proven innocent" than his criminal case should have served as "proof" that the civil case against him had no merit, but it is absolutely the case that he lost his civil case after being deemed "not guilty" in the criminal.
Said another way, being let off the hook for charges in a criminal case simply means that the prosecution failed to make their case beyond a reasonable doubt. It does not mean that the defendant was innocent- it simply means that his guilt could not be proven. In the eyes of the law, for the intents and purposes relevant to the law, he is, effectively, innocent of that crime. However, anyone with eyes of their own is still free to have an opinion, and if we talk about "proof" that we can obtain from these proceedings, it is only that he was not found guilty.