How do I stop Apache 2.4 from generating indexes?

My site is suddenly generating indexes for requests like www.mysite.com/folder/ where no index.html exists.

I've had Options -Indexes in my apache virtual host config file for years and these kinds of requests always returned "forbidden" (which is the behavior I want.

As far as I know, other than updates, there have been no changes to my site or config file.

Any ideas on why this is suddenly happening--and how to stop it?