Hello,
I had a look and I have the same behavior with CC Lite.
Clear Cache button: files deleted but repertories not deleted
Shared host: WP 4.7, CC Lite 161221, PHP 7.0.10 FPM/FastCGI, tested with cache and below repertories chmod all 705 then all 755, no debug error
Other tests:
. Local dev (Ubuntu 14.04 LTS + Bitnami Lamp Stack PHP 7.1.0 default install) with cache and below repertories drwxrwxr-x => same
. New WP 4.7 install + CC Lite 161221 on local dev with cache and below repertories drwxrwxr-x => same
. I tried another cache plugin on the shared host (cache and below repertories chmod all 705), its purge cache button have the cache repertories erased
D.