Despite running the same code and (generally) being able to see each others’ posts, different Lemmy instances (or as you called them, versions) are not run by the same people, so often have different rules as to what is and isn’t allowed on their instance. Some instances are very lenient, allowing anything that isn’t outright illegal in their country of hosting to be posted, while another instance might have far stricter rules, disallowing things like nudity or vocalising certain political views, banning users on their instance who post such content and defederating other instances (effectively pretending the defederated instance doesn’t exist and refusing to view any content posted from there) where such content is prolific.