IPS Activation as Detect cause an outage

[charlie]

Hello,

Yesterday I activated for the first time the IPS.

I put the flag on IPS and then a popup appeared with 2 option
"According to the thread Prevention policy" or "detect only"

I've set "Detect only" and on the new IPS tab a rule with Optimize appeared. But from my understanding as per popup note it's a default settings but the "Detect only" mode force the Gateway to Detect the signature with no action.
Unfortunatly the firewall start to drop the signature.

Why?

[Danny]

sk122102 - Traffic is dropped by IPS blade, while the protection is set to Inactive or Detect