Looks like the sort order was changed so that the most used templates appear at the top, in UX: Improve template filtering with usage count and preserving tags by Alteras1 · Pull Request #35881 · discourse/discourse · GitHub… but there’s no indication of this, so it can certainly appear random, especially if you were accustomed to the previous alphabetical ordering.
This isn’t a bug because it’s working as indented, so I’m going to move it to a feature request for more sorting options. Thanks for the feedback!