My theory is that uploaders are not always good, and items end up on the wrong manga, and mangago has to go back and fix it, which causes these "fake updates". I've reported several of these type myself!
So true. lol, there could be some on drugs too, you never know? (≧∀≦)
Another one is that the uploader did some changes and re upload the whole thing but the date didn't change when they were first uploaded.
Just a hunch thoug.
The plausible theory ヾ(☆▽☆) Good one.
I think mangago sometimes gives us fake updates because they want newer readers to look at older manga