Well, one of the fundamental points of having a shortcutting mechanism (like [cpan://Fisher-Yates]) is to let the user specify a search of arbitrary exactness without worrying about the implementation. If you know exactly which module or dist you want, you should be using the [mod:// ] or [dist:// ] shortcut instead. And if you want maximal determinism in the links you post, just use the exact URL.
Indeed, we've switched the implementation of [doc:// ] once or twice over the years as the "canonical" website changed. Existing links should still work pretty much as intended. And for the few old ones that do break — well, them's the breaks. I think we do a reasonable amount of due diligence to not excessively break old nodes, but really there are no guarantees.
I reckon we are the only monastery ever to have a dungeon stuffed with 16,000 zombies.