I think my replacement Zwift Cog and hub are already broken and not functioning as it should. Seems like the assembly is acting more like a fixie hub than a free hub. Contacted support but it has been a lot of back and forth during regular business hours. So the wait feels long to find a solution.
Check out the video below.
youtu.be/camTs88zoZM?si=meBeJPxvHj9R5cQw
Have you tried removing the freehub body to inspect it? There could be a broken pawl that is jamming it, or if it’s just sticky then perhaps a little lubrication could help. It seems obvious that they owe you a replacement. If you search the forum for “broken pawl” you will find some reports and pictures of that type of failure. Often it results in the freehub not engaging at all but a fragment in the right place might result in constant engagement.
Here is a video of the back side of the hub. (Sorry for the background kid noise)
(http://youtube.com/shorts/OzAY84FA65Q?si=lFAHVj0MZNy87HwP)
Wow, Zwift really makes it hard to post YouTube videos.
Wow, thanks for your fast reply. I have a few more videos on my channel looking at the hub, but it came together all as one unit so I did not want to try and break it apart. But my video does show the back side of it with the teeth.
Doesn’t look like any pawls are broken. If you try to push in those 3 little flippers what happens? Do they all move freely? You might also test it with less tension on the quick release or thru-axle, in case that is causing binding.
When you push in all the flippers it makes it so you can install the Zwift hub to the trainer when you push it onto the rod and then do that counter clockwise motion. It then clicks into place, but once you put on the retaining bot/nut then the cog acts like a fixie and you get that floppy chain action in the main video. Let me know if you have more questions!
Since it sounds like you have experienced two dead trainers, if I were in your situation I would be begging them to replace it with a Kickr Core if they can’t provide a simple repair solution. I have no idea if they would be receptive to that but it would be your best long term outcome.
I experimented with spinning the nut loosely attached, but it caused instability in the Zwift hub assembly, indicating it wasn’t the correct method. This hub is a replacement for the original one from December 2023. Initially, the first hub functioned well mechanically, but the trainer encountered distinct technical issues unrelated to my initial concerns about overlapping ANT and Bluetooth signals. After resolving Bluetooth connectivity and configuring the play controllers last month (April 2024), I began enjoying productive workouts. Unfortunately, my enthusiasm was short-lived as my Zwift hub broke. 
Thanks, Paul. I doubt they would take such action, but one never knows, I suppose. I have a genuine fondness for Zwift, and it worked seamlessly with my old CycleOps power trainer, pre December 2023. Overall, my experience and enjoyment of the platform would have been better if I hadn’t switched to the Zwift Trainer. I suspect it might even be discontinued now. It seems unable to withstand the constant strain of frequent back-to-back workouts.
And I am only level 45!
there you go
Whoa, how did you do that?
I think you have to have posted a number of times before you can post links
either that or I’m magic
Haha awesome think you could help me post this to the forum too?
Zwift Hub and Cog Not Working
/watch?v=camTs88zoZM
got it
Thanks Chris, you rock! I have to go for now, but maybe I’ll see you on Zwift. : )
no worries - hope the trainer gets sorted
I don’t have an answer but my question might help others?
What happens when you turn the pedals backwards?
It’s in the video.
-Replied from my 4a5g