If it is an activity, then edit the distance in the concerned activity. If it is the distance shown on the Steps screen, then you probably have the Custom Stride Length in your user profile incorrectly set. Adjust it accordingly.
It is an activity. The steps are set correctly and have not been altered since I set it up over a month ago. The number of steps are correct. I walking approximately a mile and it’s showing over 40 miles. The map is correct in showing the route taken. I was thinking that perhaps the sync with my iPhone 16 pro max is off somehow. So I cold booted my iPhone and tried again. I also tried turning off custom steps and I still get crazy numbers.
Once an activity is synced, it won't sync again. And even if you delete it and upload manually, it will be identical. As I wrote, to fix the past values, you can edit the activity and modify the distance.
Otherwise for fixing the issue, rather than rebooting the phone, hard-reset the watch - sync, then press the Light button for some 30s till it completely shuts down (hold the button through the emergency alert, if it comes), wait little bit, and then restart. No worry, no data or settings will be lost with it. [more details]. If that alone does not help, do the master reset to factory defaults. And if still no-go, reach out to the Product Support through their website at https://support.garmin.com.
