I use a few types/models of powermeters on different bikes. On my MTB i use a Rotor 2INpower. I have some strange issues. There is a big difference in data on Garmin Connect vs Intervals.icu
Connect: AVG 161w, NP 182w, 49% left and 51% right
Intervals: AVG 123w, NP 144w, 51% left and 49% right
Strava: AVG 125w, NP 132w, left and right not specified on Strava
I had this kind of differences af few times. It is a significant difference. When it happens often it will influence my data (fitness, fatique etc.) on intervals.
First guess would be that you have false spike detection in Intervals.
Set Power Spikes way higher (even to 999%) and re-analyse your activity to see if this sorts it out.
Unfortunately changing the power spikes to 999% did not a thing for the data. I did read somewhere that i could try to test it with a different Garmin EDGE? Although the data on Garmin Connect looks to be fine. Only on Intervals (and also Strava) differs too much,.
Power average MUST be with zeroes!
Spike setting has no influence if your power meter is spike-free. Some have spike artefacts every now and then. If so, you need to experiment with the spike setting until faulty spikes are filtered out without loosing any real data.
Post some screenshots of what is showing on Garmin Connect/Strava and on Intervals. Traces and values please. Then we may be able to identify what is going wrong in your case.
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