if there's just weird generation, sometimes that happens naturally, and is fully intentional. there's actually a specific value in the internal code of the game called "weirdness", which, as you could assume, creates weird terrain gen if that value is high in that area. however, as that other person mentioned, if you update significant versions like 1.18 or 1.8, then that can cause biome blending and weird cutoffs in the world. if this is happening to your world even if you didn't update to any significant versions, then your world may have a slight chance of being corrupted. this is more common on lower end devices such as mobile devices or a nintendo switch. the best course of action to avoid this is to avoid making the file size of the world too high. you could also make sure that there aren't specific chunks with high amounts of data in them, like a lot of chests with complicated items in them. this could cause that chunk to corrupt.
