There are a few works that I've been who reading where tags could apply, but those tags would be spoilers/plot points. In this case, do we tag the works with the tags, risking spoiling the reveals, or should we just leave them alone?
@Kie The tags should apply to the manga as a whole, even if it a spoiler. If a fantasy world was revealed to be isekai after like 300 chapters, so be it. If something only really appears in one chapter out of the whole thing, probably not worth the tag.