Hypothesis: the physical medium was a forgery, but the text was not. In other words: it was a copy of a genuine manuscrit. That would explain why the physical scroll appears to be an obvious forgery containing, retrospectively, a perplexing text.
Why would anyone go through the pains of forgery to create a copy of an original in their possession? Just sell the original if you're in or for quick money, show off your original (and sell clean copies) if you're out for status.
