Just as an example look at the “VO2 Max 3” interval from the workout below.
The workout overview shows different values than shown in the interval section. If you shift the workout view by 1 second (would be 12:31 - 14:01 in the example below) it matches again.
This gets disturbing especially for shorter intervals when the differences in watt averages get bigger.
Example ride from @Nate :