iPhone Apple Fitness doubling step distance

Apple Fitness app Steps Distance seems to be doubling even though the steps match.

Noticed it yesterday.

Using iCardio for workout.

did a workout with 6,395 steps yesterday

3.51 miles. Plus other walking not in a workout.

Fitness shows the correct steps for the day. Matches Health steps.

However, seems the distance is doubling. Total distance in Health is 4.8 miles.

Fitness shows 8.32 miles.

No Apple Watch.

Looking over previous Apple Fitness Step Distances, it seems to be doing the same, even without using iCardio.