There is an issue with the interval tables (also existing on the mobile version) when using structured workouts and a data field from connect IQ.
The workouts are grouped per types (Warmup, run....) when this grouping is the problem. Sometimes the data are missing or simply on the wrong interval.
Here a screenshot:
As you see some Power values are missing. The reason is that they are simply placed in the wrong row. The yellow one should be empty since that they represent the grouping and the empty one should be filled.
This is a bug in Garmin connect and the fit file is correct since that Power Center from Stryd or Nolio are correctly displaying the intervals.