When doing a workout in ERG mode I’ve noticed that it feels easier to go up hill and harder to go down hill - with the same power. This is very noticeable when riding at over my FTP.
For example: the workout segment requires 235 watts and my FTP is 179. On the flat the effort is tough. Climb a hill and the effort is definitely much easier even though my cadence and watts displayed have not changed. Come to the downhill section and the effort gets way tougher (again with same cadence and power displayed). On one hard workout the downhill section increase in effort brought me to a standstill.
I’m using a Tax Neo and experience no other issues with my setup.