My answer to this is quite simple: Show proof that they're wrong in-story. Doesn't have to be blatant, doesn't have to be screamed, but if you have a reader who is detail-oriented enough to pick up the flaws in a character's logic, they'll be detail-oriented enough to pick up on the tiny consequences that foreshadow the big one.
Use Bad Logic as the Villain's Character Flaw
Logic is an abstract concept. Bad logic is a character flaw.
In most characters, character flaws lead to conflict and growth. They influence the outcomes of that character's actions, and a character might reflect on them or change because of them. They help readers empathise as characters struggle.
I'd rarely skim a fiction since it has some continuity, but articles are different. Article is supposed to provide information, and if the information density is low, I'll start skimming and looking for things that are actually new and interesting.
Especially with the boom of click-baity internet magazines, I often skim a lot of the article. So keep in mind ...
In your particular circumstance: No. That is not normal.
If I am given something to provide feedback, then I will read it all; OR I will read it all until I have seen enough to not bother reading the rest. Then I will provide my advice, and if I didn't finish it I will tell them where I stopped, and why I stopped.
Usually if I stop it is because the same ...
In my experience, it depends on what is being read.
Personally, I often skim large parts of technical material. I am often reading for something specific and I skim until I find it. I often then stop completely. So, for non-fiction material I would say skimming is fairly common and for material that is at least partially meant to be a reference skimming ...
In Technical Writing, it's expected that readers don't want to read what you write. In fact, I used to teach with a book with that on the cover
(see the notepad):
(basically - Tech Writing people only read the bits they NEED for the info they need to make a decision or take action. For fiction, though, things are for pleasure, and while people may read ...
In my experience, people don't do this for significant part of the writing. It may happen to skip a sentence or two if, either:
the passages are not clear,
the reader is tired,
there is a "wall of text" effect
the narration style is boring, repetitive or dragging
While you can't do anything for point 2, you can somehow fight against 1, 3, and 4.
Many readers definitely will skim over parts of your writing. In my experience there are three primary reasons for this.
Your writing is boring or drags. If a book spends too much time describing seemingly irrelevant details, I think I can predict exactly what is going to happen, or I don't feel invested in the characters in the scene, I'm liable to skim ...