To clarify, this post is not about one of those bugs that involve a desert temple spawning in a village that clips into the houses or a village spawning over a ravine causing some rather "funky" looking villages, no, I'm talking about the hidden hitboxes in those structures that decide whether that structure has special mob spawning e.g. witches spawning in a witch hut, blazes in a fortress, pillagers in an outpost, etc. So what's happening in this case is that a pillager outpost and swamp hut go to generate but get the incredibly slim chance of both hitboxes clipping into each other and in this case the game selects the pillager outpost as the primary hitbox can prevents witches from spawning in the entire witch hut hitbox which should NOT happen and instead pillagers take their place although cats still spawn normally

Screenshot 1 is of a Pillager that has spawned in the witch hut hitbox (the hitbox has been cross checked with a modded client that visualises structure hitboxes and mob spawning checked several times), Screenshot 2 is showing how weirdly close both structures are and screenshot 3 is a modded client with a mod that visualises structure hitboxes in a void world but same seed

The version is 1.18.2 and has no mods installed whatsoever other than screenshot 3 and the seed is 237571016 and these two structures are right beside your spawn location

It's very likely I've made some big mistake in writing this but feel free to correct me on anything here, I'll likely respond quickly

TLDR; Witch hut and Pillager outposts have hitboxes that overlap, Outpost completely overrides witch hut spawning and witches no longer spawn there