It's a trivial difference (taking some grain and eating it vs taking some grain, mashing it in your hands, and eating it), so by "secret Bible verses" standards this seems plausible as either a scribal error, a translation error, or an accurate bit of scripture that wasn't correctly copied into later manuscripts.

It's more interesting as technology for evaluating old vellum manuscripts than any theological significance.

They didnt. It was a common practice to scrape the top layer off vellum manuscripts and reuse them. UV light allows modern scholars to read some of what was originally written before it was scraped off.