Web proxy problem

Hi all, I am a newbye with hAP ac lite, ROS 6.35.4 (stable).

I need to cache the one small web site for access from LAN only.
I turn on web proxy and set rules for caching that site and passtrough any other.
All work fine, but it does not save after rebooting.

I check on Cache On Disk and set Cache Path - flash/wp.
After turn on webproxy the used memory in File List windows increase to maximum size.
And Proxy does not work.

After turning off Proxy service I delete falsh/wp directory.
But error occurs. After that I can remove it completely.
And I see many subdirectories like cycled making.

I know that flash is not good space for proxy cache.
But it is my special need)