It turns out that since Mastodon 3.0.1 only the first four hashtags in a pinned hashtag search column actually work.
There's no warning, no error message, and no limit to the number of hashtags you can put into the box. It just... fails silently.
@cassolotl It's even worse, posts with other hashtags show in my pinned search column as well but don't stay there after reload. Only the ones with the first 4 hashtags do.
@ondra !! That's so unnecessarily confusing!
A silly instance of Mastodon for queer folk and non-queer folk alike. Let's be friends!