Activity tracking showing as distance ‘FT’

As currently configured, your watch will show shorter distances in feet and longer distances in miles.

Apple Watch and your iPhone choose default units (metric or imperial) based on your region.

Check the Watch app on your iPhone:

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• My Watch > General > Language & Region > Region format
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You can also check on your iPhone under:

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• Settings > General > Language & Region > Region formats
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Units used by the Activity app and Workout can also be changed as follows:

On your iPhone, in the Health app, go to: Health Data (tab) > Activity > Walking + Running Distance > Unit

Or on your Apple; watch:

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• Open the Workout app and select to start an Outdoor Run.
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• When the goal screen is displayed, swipe left / right to the distance goal. Press firmly on the screen, then choose kilometres or miles (if the other is originally shown).
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• Exit from the Workout app (go back one screen by pressing cancel, then press the Digital Crown).
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• The Activity app will now show your chosen unit (which will also be used for future workouts in the Workout app).

From JohnathanUK

Until we can resolve it you can divide the the ft by 5280. Try a restart/forced restart - How to restart your Apple Watch - Apple Support

then try going here - Get the most accurate measurements using your Apple Watch - Apple Support

Make sure your watch and phone are using the latest update too

Check the watch app on the phone too to see if for some reason something is not set correctly there.