If you accidentally left Go & Track running too long or started it too early, you can remove unwanted sections from a saved Track using the Trim Track feature in the onX Offroad App or Web Map.
How to trim a Track in the onX Offroad App
Click or tap the Track on the map to open its info card and swipe left on the options at the bottom of the card to select Trim Track.
Move the green scrubber to the right to trim the beginning of the Track, or move the red scrubber to the left to trim the end. Tap Save when you're done.