By default, LR shows the times of the tracklog in your local time zone (which I assume is UTC - 7, e.g. PDT). So there's no need to apply a time zone offset.
The most efficient way of troubleshooting this is to upload the tracklog along with a sample pic to Dropbox or similar and psot the link here. Then we can take a look at what's going wrong.
The sample photo you included already had GPS coordinates assigned. So the Auto Tag command gives "No matching photos" (it only reports the number of photos which are on the tracklog and previously had no GPS coordinates) .
I removed the GPS coordinates within LR and then the Auto Tag command reassigned them. My computer is running in UTC-7, so I didn't need to adjust the time-zone offset. Interestingly, the coordinates assigned by my LR aren't exactly the same as the original -- did you use some other tool to assign them?
Before: 37°39'58" N 122°21'37" W
My LR: 37°40'35" N 122°21'40" W
Thanks! Everything working now.
I just loaded the tracks which I downloaded from Garmin connect to Lightroom.
Things that helped:
Lightroom automatically assumes the current timezone so you have to apply an adjustment from your current timezone to the camera time zone.
Once a timezone has been assigned it isn't overwritten by a subsequent attempt. You have to remove the already assigned coordinates
So it looks as if the workflow is:
1. Use a filter to select via metadata the pictures that were taken for that day.
2. Load in the track file for that day.
3. Add a timezone adjustment for the difference between the current timezone and the camera timezone.
4. Select all of the pictures for that day and then auto tag the photos.