I am using a Zwift Hub along with a Power2Max.
When I first got the Hub, the Hub read about 70 watts too high compared to my crank based meter. I re-calibrated the Hub, and the accuracy became much better, but still ran consistently about 10 watts lower than the P2Max.
I updated the firmware on the Hub, did the re-calibration procedure, and now the Hub reads about 10 watts too high compared to the P2Max.
Before firmware update (230 vs 240 watts):
Strava is the Hub data, Intervals is the P2Max data
vs
After firmware update (156 vs 146 watts):
vs
