Calibrated pace in training different in group runs

I am using the Zwift Runpod and after a few tries I was able to get my calibration to a point that the speed it shows I am running in the app is very close to what my treadmill displays says. However, when I joined my first group run last week, with no changes to the calibration, it said I was running much faster than my treadmill readout. For instance, setting the treadmill to 5.8 mph gave a speed reading of 7 mph in the app. Doing a training run, the calibration was accurate again. Any ideas what could be causing this and how I could fix it?

(Based on other topics in the forum I’ve gone and purchased an NPE RUNN device but I’m still curious what the problem is.)

I suspect your training run pace was different to your normal pace. The workout tend to go up and down in pace rather than a consistent speed like you’d normally run at.
The runpod and to be fair the NPE Runn seen better at varying speeds. It depends on the pace you calibrate it at. I’ve found the Runn can be better if you calibrate it at slow speeds.