Five Tag Limit?

Hey, I just figured out that if you tag a post with dozens of tags, only the first five are searchable.

My tags generally fall into two categories: rambling, nonsense commentary tags and actual meaningful search terms like names of shows and characters.

If I fill up the first five tags with rambling commentary and put the character names at the end, random passers-by never find my post and my followers are the only ones to reblog. If I put character names at the beginning and leave the commentary to the end, strangers do find my post.

If I search for my own post, I can only see it when I use one of the first five tags as a search term. Weird.

Does this have something to do with the tumblr Community Guidelines clause against “tag spam”?