Total ascent different from elevation gain for a stair climbing activity

I did an outdoor stair climbing activity this afternoon in an attempt to get all the new Garmin Badges (Record a floor climbing activity with (334, 735, 1000 and 1500) feet of ascent.)

For some reason, however, Garmin Connect shows that my total ascent is different from the elevation gain for the activity:

Now, my understanding is that elevation gain is exactly the same as total ascent, is that not correct?

Here is the ascent graph for the activity:

What is bizarre is that I was tracking the total ascent on my watch during the activity and it shoes 473m indeed as seen bellow:

p.s. "Elevation Corrections" is off on the activity