Hello there, Paul Mirfin. Thanks for reaching out.
We've recently received reports about the duplicate trips tracked in QuickBooks Self-Employed (QBSE), which has already been resolved. In your case, since you still have this unexpected behavior, I would recommend reaching out to our Customer Care Team. Our representatives can send another request to escalate this to our engineers for investigation.
To reach them, click the Assistant button at the top-right corner. Ensure to review their support hours, so you'll know when agents are available.
In the meantime, to ensure that the auto-mileage tracking feature is working, I recommend first checking that the device operating system is up to date.
Adding you also some articles to guide you to check that all the settings of your mobile device are properly set:
If you have additional assistance while managing QuickBooks, let me know. I'll be around to provide further assistance. Have a nice day.