ERG Interval drift of trainer vs power meter

Anyone else having issues with ERG mode drifting? Running a Zwift Workout to Neo2 the power reports on the screen for the prescribed watts for the interval. When simultaneously recording the data to my Quarq Dzero the power doesn’t stay consistent. Say I’m doing intervals with multiple repeats at 180w on the Neo2 controlled by Zwift. Recording the data to my Garmin 520 from the Quarq Dzero it may show the 180w interval as 177w in the first set and 170w in the next set. Seems to vary 2-8% lower than my Neo2. When riding in free ride during the Tour de Zwift the powers seem to be spot on with 1% accuracy.

I’ve tested my Neo 2 against Stages Dual, Vector 3, Stages L and a second Quarq Dzero last year but just realizing with this new Quarq and some new testing there seems to be issues with accuracy in ERG vs Freeride. Possibly why I kept getting different results in my testing last year and started to lose faith in powermeters. One day they would be spot on and the next off. I didn’t notice the ERG vs free ride thing and may need to look back at that data.

I need to try an ERG workout in trainer road and see if this is a Zwift thing.

Sorry. It won’t let me post the zwiftpower links for all to see in this post.