IPS Service - with no FW rules - Prevents Certain Sites from Loading

I'm running V19 in bridge mode.  Very basic setup, haven't really gotten far with it yet.

I've noticed that even though I have no firewall rules with IPS enabled, certain sites - like this one(!) time out unless I stop the IPS system service under "system services -> services" - And I'm not seeing any errors in /log/ips.log.  When I disable that system service, the problem stops.

Here are my firewall rules:

(Note I disabled the default NAT rule because this is an internal bridged setup, no NAT needed).