If you do a workout and at some point during the workout change the bias to increase or decrease the power targets it updates all of the power targets including the ones you have done. In my opinion it should only alter the power target of segments still to come.
I did a workout today where I was finding it pretty comfortable so for the last couple of segments I ramped up the bias eventually ending up at 110%. This changed the power targets of segments already done. In the attached screengrab as an example I actually did the 5 minute segment at 100% of FTP / 300 watts. However when I ramped things up later it gives the impression I did it at 315 watts which is wrong.
I would almost call this a bug.