Your issue is the same discussed here.
There is unavoidable lag for trainers to adjust resistance. TR tries to offset this delay by sending the resistance adjustment about 1 second early.
In short, ignore the actual interval summaries in the app during the workout, and table in post ride analysis. There will likely be a differential that will make it appear that you “missed” the interval.
But, when you look at the zoomed in intervals you can see that you get the overall time and training effect desired.
- Here is my more detailed explanation from that thread
Erg mode slow to react - Tacx Neo, Ebbetts Workout - #8 by mcneese.chad - Review of another riders data.
Erg mode slow to react - Tacx Neo, Ebbetts Workout - #20 by mcneese.chad
To add:
- One trick I use for these intervals is to slow my cadence about 10 rpm slower than planned cadence for the interval. I do this about 10 seconds before the start of the interval.
- When the timer hits the start of the interval (the resistance is already swinging up from the 1 second jump start) I jump hard and get up to my planned cadence.
- This can ramp up the power a bit quicker to get closer to the target power sooner.
- It’s not perfect, but helps if you are concerned about the lag.