There are many reasons for typos in ancient books:
First, as my friend said earlier, the change and increase of the meaning of ancient and modern words actually do not belong to the category of "mistakes", but are the product of language development and change.
Second, before the unification of characters, ancient books had different writing habits according to different regions. It was not until Qin Shihuang unified the writing that this culture became popular. At that time, Chu, Qin and even Qilu all had their own writing styles. Therefore, when they spread in different countries, the misunderstanding and writing in recognition and reading will continue to future generations.
Third, before the invention of printing, most ancient books were copied. Therefore, when copying, there will be "mistakes", "losses", "deviations" and "omissions".
"incorrect" is what I said above. I read the word wrong, but later I was wrong because of my mistake.
"Seize" refers to mistake one word for another, or in a serial way, in a series of articles, in a series of simplified words, and so on. This is also related to the binding method of ancient books. If the binding rope is broken, rearranging the arrangement order is a big problem.
"Yan" refers to adding words when copying, and then passing the whole article to future generations by mistake.
"Leak" means that when you copy, you miss the original text and the words.
Fourth, there are many problems in copying and sorting out these problems. When carving on stone or wood, if the engraver is careless, lazy or poor in craftsmanship, or there is not enough time, there will also be changes and omissions of words, such as too many variant characters, too many simplified words and too many missing words. If you don't proofread it in time, once it is reprinted into a book, the wrong fixed pattern will become the norm.
Fifth, ancient monarchs often promulgated taboos of various times. Once encountered, the word "consent" should be used instead of the original text. Later generations sometimes don't know that they mistakenly regard the replaced text as the earliest version, thus forming new mistakes. However, after the Ming and Qing dynasties, taboo words were treated as missing pens, which was easy to understand and modify.
Sixth, ancient celebrities often made their own words, but later generations didn't observe them and mistakenly thought they had typos.