When I was a Strange Horizons editor, we used to occasionally receive stories in which the title gave away a major surprise plot element. I always thought of that as a kind of beginning-writer mistake, but I see now that apparently it was considered a reasonable thing to do in sf written circa 1940.
For example, in the classic 1946 Healy/McComas anthology Adventures in Time and Space, there’s an Eric Frank Russell story titled “Symbiotica,” in which the eventual big surprise is that the aliens turn out to have some kind of symbiotic relationship. And there’s a Maurice A. Hugi story titled “Mechanical Mice,” in which the mysterious machine from the future eventually turns out to make mechanical mice. And in Harry Bates’s “A Matter of Size,” the protagonist eventually discovers a surprise having to do with his physical size.
In each of those cases, the surprise that the title refers to isn’t revealed until at least halfway through the story, so the reader is left impatiently waiting for the protagonists to slowly figure out the thing that the title revealed at the start.
One might argue that these titles indicate that these stories aren’t intended to surprise readers—but in each case, the stories are structured as the protagonists encountering mysterious situations and gradually figuring out the answers to the mysteries. That’s not the only thing going on in the stories—the “surprise” reveals aren’t at the ends of the stories—but it is a major part; if the surprise isn’t meant to be a surprise, then the story shouldn’t (imo) build it up as a mystery.
But the editors of this major anthology considered these stories to be among the best available, so clearly there were other sources of reader pleasure involved here. But even so, I feel like all of those stories would have been improved by either having titles that gave less away, or having plots that didn’t focus so strongly on mystery/revelation.