I’ve recently encountered this problem, as shown below.
I haven’t encountered this problem like Liz Jones did above. In this case, I was doing a set of 3 over-unders that were 2 minutes @215W, 1 minute @240W (arches should be orange and red). Above, I was at 215W, heading to the segment that requires 240W.
I wonder if this has something to do with how the software handles intervals. Below is a code snippet from the .zwo file for this custom workout.
<IntervalsT Repeat="3" OnDuration="120" OffDuration="60" OnPower="0.95449996" OffPower="1.0545" pace="0" OverUnder="1"/>
This is how you define any interval. The first field is the number of repeats. Note how the first field is always “OnDuration” or “OnPower”, and the second is “OffDuration” or “OffPower”. In this case, I’m going easy then hard. It’s always in workouts like these where my arch colors are messed up. I have workouts where I have the intervals set as hard, then easy (e.g. a regular set of VO2max repeats), and the colors are normal. Perhaps Zwift is hard coded to show the “Off” interval as blue.