When I create workouts that have long intervals it would seem the total elevation changes for the interval are not being calculated correctly. You can see in the image below for the warmup the three individual kilometres in it total 34 (6+19+9) and for the first 5km workout interval total 23 (6+6+0+2+9). But for some reason the total for the interval is about double that.
I imagine its just something wrong in how its presenting the data as everything else seems correct except that total number.