I also started a ride with my Edge 1030 showing 98%, and by the end of the ride, it has increased to 100% and gets stuck there. One ride, after a firmware update, the gauge started at 74% and it steadily increased over the course of the ride to 94% (and no, there wasn't an external battery connected.). Obviously there are some significant math mistakes in the Edge 1030 battery gauge firmware.
Can you share the .fit file from this activity?
Well known bug that’s been around a while, see this thread (and a few others)
@Garmin-Matthew
I found it! (It only took me a couple years)