It would be considered an outlier, but it’s certainly not impossible.
Did you get the 198 by historical data or did you use the 220 - age formula?
The form of the curve does not really make sure if it is an artefact or not. Do you have multiple occurrences of similar values?
Here’s a chart from an older study. The straight black line defines the 220 - age.
If you want to read the article that goes with it: