@tommyexmoor, everything looks fine to me. I recently got the Duos and also have a Kickr Core.
By default, the Kickr has its own power smoothing enabled so it typically has the smoothest power output of any of the equivalent trainers (e.g. Neo 2/2T, H2/H3, etc). You can disable it via the Wahoo app (more on why I did this below). Note that enabling / disabling the Kickr’s power smoothing does not change its behavior in erg or any of the modes (standard and resistant being the other two), it only smooths the broadcasted power.
When I first installed the Duos I wanted to ensure they were tracking to the Kickr. I dual recorded an activity on my head unit and used ZwiftPower’s free comparison tool. You need a ZwiftPower account but do not need to subscribe to Zwift. ZwiftPower.com → Profile → Analysis. One of my first comparisons is here.
I then turned off power smoothing on the Kickr via the Wahoo app. Pictures before and after are here, and look similar to yours.
After turning off the Kickr’s power smoothing the Duos track even closer to the Kickr. Although this morning’s workout was a total dumpster fire, the Duos and Kickr tracked nearly identically.
TLDR: You’re good to go!