Missing timezones in postgres 17.2

For some reason, `postgres-flex:17` (which is running 17.2) is missing timezones. For example, `select * from pg_timezone_names where name like '%US/Central%';` returns nothing, and this causes problems for my application. I don't see this problem when running 17.2 from other postgres images that aren't from `flyio/postgres-flex` and I haven't found release notes or anything that says timezones have been removed. I also don't have this problem with a new managed postgres cluster. We also didn't have this issue in earlier versions of postgres-flex, specifically 15.6. If anyone knows why this is happening, I'd love to understand the source of the issue. Thanks.