Squid settings not honored.
In my ongoing question to get squid working I've tried this option.
Keep Settings/Data If enabled, the settings, logs, cache, AV defs and other data will be preserved across package reinstalls.
Note: If disabled, all settings and data will be wiped on package uninstall/reinstall/upgrade.
Settings are preserved regardless of being checked or not.
That wouldn't be specific to 2.3 then, you might have better luck posting that on the Proxy board.