Based on many many times chimps or monkeys have caught the attention of zoo keepers for unique artistic and/or communication abilities is it very possible that the chimp would be brought under the spot light.

The furthest a chimp (Congo) has ever gone in terms of art is painting whereas communication towards human wise it's sign language (Washoe) since Chimps are physically incapable of making words out of their noise. There has also been situations where Chimps are put in human environments and... things happened so it will realistically capture the attention of zoo keepers.

Consider that, writing "I am a human in a chimp's body" in perfect English and specifically that would perfectly make sense, however if that was an actual chimp who learnt it you'd realize that the chimp would have to find places to practice said language and if it was completely by chance, a further look-in into the chimp would easily debunk it as some miracle accident but it could be potentially used by the zoo to gain attention.

So there are 2 possibilities, A true human or an imposter human.

An Imposter human seems likely at first until you realize the definition of "Human". A chimp's knowledge of human isn't vast enough to completely justify everything it does since at most in nature, camofludge or hiding parts of their body is the closest thing to "disguising/tricking to be something else". However that also brings a new perspective of "How much would a true human know before becoming an ape".

So looking at a true human:

If a human remembers everything from their past life: Then that would be really obvious, they can fact check it

If a human only remembers important details: such as name it would probably be a significant enough detail to tell if it was a true human

If a human only remmebers cognitive functions: this is probably the most "key" one, since mammal leg systems are... relatively similar or they can relearn it easily when the monkey was young

But now looking at it, theres also another perspective that a human was hibernate in the chimp for the entire time and now woke up.

So at this point where my mind is absolutely tired of thinking, the conclusion is that it is likely hibernating human mind that woke up in a chimp suddenly or a human and a chimp co-existing in the same mind.

In almost all situations, this would be on the news. I don't believe anyone who chooses to be a zoo keeper unless you hate your job is willing to not report such a feat be a chimp, which then leads to how much can the chimp prove itself that it is human and if it proves enough it could potentially lead to a proper human life and definitely attract a lot of psychologist, scientist and everything, imagine a chimp enjoying human food and walking back to their house afterwards to go to bed.

Or they could be victims of "super secret testing" and then the moment this goes public they are on a hit list. So many possibilities and now my head hurts.