Isn't that cause and effect? That is right sometimes? Through dumb luck? What did I miss? (genuine question, because I read what you say above, and it's just saying the same thing differently.)
At times like this, I wish I had a whiteboard so I could diagram what I'm talking about.
So there's two ways of thinking about cause and effect here-forwards and backwards. You're thinking forwards which I think is what's causing the confusion.
To a forward thinking: You have a cause and effect. So doing A causes B. If you don't do A, B won't happen, and if you do C, D might happen. People sometimes get lucky with guessing that B will happen from A, without really knowing. But you can easily test this and mess around with variations of A and see how that impacts things and get a pretty good idea of what's happening. That's how a lot of experiments are run nowadays.
Now for the backwards thinking: You have an idea that A caused B. Rather than continuing working out the "why" from the A standpoint, and putting in variations of it to see the different results and what comes up, you just kind of guess why it happened. This is where you end up with some folk wisdom and pseudo-science.
The thing is that it's not dumb luck, since they've already determined A causes B, they're just trying to fill in the reasoning afterwards. So for instance, relaxing your shoulder before you punch can cause a stronger punch. That is cause and effect, but it's not dumb luck that they figured that out. And it's always going to be right (assuming both ends of the equation are tangible), since if it doesn't reproduce the results, people will stop assuming it's correct. But then you get people making up reasons why it works, and that's the falsehoods, saying it works because it means your fourth chakra was aligned, or it's a sign you had control over your emotions, or something else.
A more concrete example would be the seasons. If you look at ancient greece, they knew that when winter came, crops died. They could pretty distinctly tell every time around november (or whenever crops die in greece), any crops would whither and die, and leaves would fall off the trees. So they have both cause and effect, but it's not dumb luck that they figured it out, it's pretty obvious. Then they decided they'd figure out why, and determined that one god kidnapped another goddesses kid, and keeps her for those months, and the mom goddess happens to be the goddess of the crop so she cries and mopes and everything dies. Rather than that the earth tilts and rotates. So they could figure out both cause and effect, and it's not dumb luck, but if someone came up to you and said that this guy kidnapped that girl and now my wheat won't grow, you'd probably call them crazy.
Hopefully that makes sense. It's one of those things in my head I can think about it perfectly, and if we were talking about it, I'd probably be able to explain, but tough over text.