My Health app had recorded 15000+ active calories on a day in April and when I checked the data I found out that Garmin Connect reported some date 50+ times in a row all with same timestamp and info. Had happened on other days too but not with 50+ reports only 4-5
I'm using the old SE iphone with the latest iOS if that helps.
Update: Now looking at it I'm guessing only one of those entries should exist at all. There's a regular entry at 22:59 which I'm guessing is the sum entry for the day.