Average power discrepancy between Garmin Connect and Strava

Ever since swapping to the Magene Powermeter, I'm experiencing the issue that the avg. power between Strava and Garmin Edge 830/Connect is quite different from the values shown in Strava.

I saw in other threads that you've quite a lot of knowledge about this topic. I had a look at the fit files. It seems that the accumulated power(watts) that are saved in the fit file are causing this issue. As they are higher than what I have calculated for the accumulation.

Is there any solution for this issue?