phpBB Command Line Interpreter does not clear /cache directory

I am in a localhost test environment updating from phpBB 3.2.5 to 3.2.6. I clear the cache with the command line interpreter as:

>php bin/phpbbcli.php cache:purge

[OK] Cache successfully purged.

The /cache/production directory is not removed. I remove the files as:

>rm -rf cache/*

After updating to phpBB 3.2.6, the command line interpreter leaves a single file in the /cache directory. Alternatively, the /cache/production directory will remain.

I can repeat this behavior in the Administration Control Panel --> Purge the cache.

I expect a cache purge to remove all files in the /cache directory.