Power smoothing is only during the workout, it’s not in the historical data like you are showing here. If you are using a Wahoo trainer in ERG mode they have a very good power smoothing but you must have turned it off in the wahoo app. Other trainers might have their own power smoothing also.
I know it’s doing it while riding the workout. That’s exactly what draw my attention few days ago, because the live plotting is full of jigsaws, when it was pretty good before.
The ERG timing adjustment for each intervals is EXCELLENT, spot on !! please don’t touch that