Possible bug Squid Transparent Proxy
I don't know if it is intended or it is just a bug.
When I enabled the Transparent Proxy and using Android Chrome browser with "Data Saver" On the transparent proxy will not work, it still loads pages but without filtering e.g. porn sites.
However, if I manually set the proxy on the wifi setting, and enabled Data Saver the proxy will work as intended e.g. porn sites are filtered.
Chrome for android has been automaticly direct proxy system by google. ;D