training impulse 4917 in a random event

In my 2 years history I have this one event that is 1-2 orders of magnitude outside of all the other activities. 

I do occasionally do smashfests, where I'd run an ultra really strong, but this event is just a random bike ride. I even aborted it because I was tired.

The "training impulse" of that ride is 4917. For comparison the Annapurna 100 race that I finished second two weeks ago I got 513 points.

Is this a glitch? If not... what happened?