After skimming the first few paragraphs, I almost commented something similar to yours. But after reading it until the end, the problem is more nuanced than that.

The issue is more about reusing memory that has been allocated when you "convert" (in Rust term: into_iter()) a Vec to another Vec. More surprisingly, the reuse still happens even when the new Vec has a different type than the original Vec's type. You should read the whole post—it's more interesting than I (and you) thought.