Generally speaking, there are several links in publishing a paper: self-inspection, tutor inspection and editorial department inspection. The most important thing is to check this step yourself. If the editorial department finds typos, it will send back suggestions to you.

And when you passed these links, you didn't find any typos or fish that slipped through the net. This situation also exists. If you download the files directly, you will find that some of them have typos. It seems that the author is nothing.