Deleting "folders only" folder doesn't actually delete

Hi,

I'm using dovecot-2.3.17.1-1.fc34.x86_64 on fedora34 and Thunderbird 91 on fedora35. When creating a folder of type "folders only" in Thunderbird, then trying to delete it, it doesn't actually delete it from the filesystem. Is this a permissions problem? Or perhaps a Thunderbird problem?

I don't see any messages in the logs that would indicate some type of failed attempt to delete. How do I troubleshoot this?

Thanks, Alex