Each Sensor model has a limited throughput. For example, the Trellix IPS M-2950 Sensor is rated at 1Gbps performance. With the Gigabit interfaces it is theoretically possible to cross the limit. What happens in this situation? Will it throttle the throughput to 1Gbps or will you just lose the IPS functionality for everything more than 1Gbps?
The answer is that the Sensor will drop packets irrespective of the TCP flow violation settings. We also have the latency monitor feature where the Sensor can inline-forward traffic without IPS inspection if it crosses the limit. There could also be false negatives and the traffic might experience high latency.
It is very important that you stay within the operating parameters of the device you deploy. If you are actually running at gigabit speeds, you should probably be running an M-3050/M-4050/M-6050/M-8000/NS9100/NS9200 and NS9300 Sensor, which all have a much higher throughput.