Erratic watts

Hi. I have an elite suito. During workouts my watts are very erratic - let’s say I’m targeting 200 watts, my output bounces all over the place every second from say 175 to 230. My girlfriend uses a Tacx vortex and her power stays as flat as a pancake. I am a much more regular cyclist than her so don’t think / hope it’s not me that’s the issue! Are such erratic readings normal? Or is it because my trainer is more accurate? Or perhaps is it because my trainer (only 3 weeks old) is not working correctly? Thanks for any advice…

I have the same trainer, which arrived today.
I’m experiencing the exact same issue. ERG is unusable. When starting a workout the resistance on the trainer is extremely hard and the power fluctuation is ±100W

Is this perhaps an issue of power smoothing? It’s natural for “instant power” to fluctuate since power varies over the pedal stroke, and there’s no way the rear hub can tell how to average over a single pedal stroke (unlike crank-based power). I wonder if different trainers use different averaging.