Power spikes in workouts

Training
1

I completed FTP Progression 1: 5x6 earlier today and experienced several power spikes throughout the session. They were not listed as part of the workout profile, and they felt planned in their frequency and duration. Wondering if this is an embedded feature or a glitch in the session. They ended up making the session more interesting, but not knowing they were there resulted in some start/stop repeats at the beginning.