I have contacted suunto support and seems that they are not aware of this problem.
Has anyone the same issue but with a different power meter brand than Favero?
Here the reply from Suunto Support:
"Thank you for bringing this to our attention, and I’m sorry to hear you’re experiencing issues with the cycling power meter data on your Suunto Vertical.
This is the first time I’m hearing about this specific issue, but I will definitely forward your report to our team for further investigation. Since the Assioma Favero Duo is a third-party device, it’s also a good idea to check with Favero directly, as sometimes firmware glitches, sensor calibration, or connectivity problems can cause inaccuracies.
We appreciate you sharing the forum link, and we’ll look into this closely. While I can’t provide a timeline just yet, we’ll keep you and our community updated as soon as there’s progress.
Thank you for your patience and for helping us improve the Suunto experience."