Same here now.
I thought it might be a “not in the DOM yet” thing. but testing with my longest localhost topic (109 posts) an in-topic search found the last post without a problem
I thought it might be because of deleted or system action posts interfering with post count - topic length. but again in-topic search found the last post OK in a couple of ~40 posts topics that had non-posts.
I know there can be at-first-unexpected results where quotes and emoji names can be returned. And there are some stop words such as “the”, for" etc. but trending and hashtags wouldn’t be in those, except maybe quotes.