Normally, "instantaneous" readings, (data spikes or very short-term valid excursions) are filtered by the design of the FOQA Event usually by requiring a certain amount of time, say 3 seconds for example for a high-rate-of-descent Event, to ensure that that's what was going on, and it wasn't just short, transient, ("going through the red light") value. Excursions occur all the time, and, particularly if the approach is rapidly re-stabilized, our program leaves such excursions out of the data. We call crews, we do not send emails and the discussion is a welcome one as the crew is often as curious about what FOQA shows as we are about learning from the occurrence.
Also, I am a very strong believer in pilot-run FOQA programs, or at least having active line pilots watching the data on a regular basis and doing the crew contacts under the direction of the FOQA Program Manager. I know this is may seem unrealistic to many but in my experience, (running FDM since the late 80's and flying the line), avoids many of the pitfalls like the one being cited here.
FOQA Programs need to be tailored to the airline's operation and designed and implemented to reflect the air carrier's safety culture. To reinforce something stated above, there are as many ways to do flight data monitoring as there are programs and no two are alike.