Problems with Garmin 305 total time and trainingpeaks

When I use the garmin 305 for any indoor training, running on track, spin class, etc. when I download the total time into trainingpeaks, the total time is off.   For example, if I run 30 minutes it might say something like 14 minutes total time, if I ride spin for an hour it might say 27 minutes. This does not happen in any other software program, sporttracks, garmin connect, etc.  Any ideas?

Thanks.