Can't find flight from New York to Miami spoiling my Lifemap

I had two long lines on my Lifemap which were a real eyesore: on from Europe to New York, the other from New York to Miami
I managed to find the Europe to New York in Garmin, download the file, remove the trans-Atlantic flight, and upload again.
But I cannot find the New York to Miami! I’ve searched Garmin by distance, and it doesn’t show up. Any idea how to find it? James, can you help?

If you are using strava Strava Multiple Ride Mapper is a helpful tool to identify activities with bad gps-data as you can click on the lines in the generated heatmap. Find the activity. Crop the activity in stava. Delete it in citystrides and sync.