Strange behavior on 6.5

Hi,
I have setup account and associated group 'children' to it.
On the policy, I have allowed use of internet within specific time period.
Proxy was running with authentication feature but not filtering and the default port was 3128
When I activated the filtering, the web browser got a message to use port 8080 for the proxy. So I did the change.

But when using the children account, I was able to browse the internet outside of the specified time period.
Nothing shown on squid log as if the time period was not taken in count.
User is associated to the group and policy is associated to the group too

Any idea what could be wrong?

Thanks.