1. Create a new glossary with autolinking enabled
2. Add a new glossary entry
3. Enable the Glossary filter
4. Add some text to the course page to show the glossary link
5. View the dev tools => Network tab, and reload the page
   1. Note: first.js loaded
   2. Note: event.js loaded

I'd hazard a guess that requirejs is loading first.js async in the background at the time that event.js is loaded, and as a result event.js is also fetched.

Ideally requirejs needs to only load -lazy items, but I don't think that's possible. We may have to change the requirejs loader to load first.js sync so that it blocks but that's not a great solution either.

https://moodle.org/mod/forum/discuss.php?d=377578#p1559908