P: Problem with Tracklog

I created a track on my cell phone for several photo sessions in California. Upon returning to North Carolina I loaded the photos and tracks into LR, but when trying to Autotag received the message "No Matching Photos." I tried to set a time offset, but when I selected the menu item nothing happened. I did notice that when I tried to autotag the photos LR started an "operation" (in the upper left corner) but nothing ever happened - that notification stayed up there - never completing - until I closed the program.
Upon examination I noticed that the tracklog had a time offset already built in. When I removed this the tracklog worked as expected in LR.
I can supply the logs if you need them