This reporting is the normal behavior for devices that are very busy. In this example, the error "Regular Expression exceeded engine time limit (100000)" indicates that filter 13593 has exceeded the allocated time for inspection. It could be that the filter may be misbehaving or it is stuck in processing. The second line indicates that because of the delay, filter "13593: HTTP: Adobe Reader PDF Widget Object Use-After-Free Vulnerability" has been temporarily disabled by the IPS. To reset the filter to your configuration setting, redistribute a profile, or DV update, the filter will no longer be disabled.

What is Adaptive Filtering Configuration?

Adaptive Filtering Configuration (AFC) automatically manages your device under extreme load conditions. The device can be configured to protect against the potential adverse effects of a defective filter. On rare occurrences, the system may experience extreme load conditions that may cause the device to enter High Availability due to traffic congestion caused by filter failure.