Hello,
Thank you for the logs and explanation, these are both helpful.
I can see the link auto-negotiation is failing. At this stage, I believe the hardware is fine.
Do you have auto-negotiation configured on both sides? If you only have one side, then you would get a
duplex mismatch.
If you are sure both are in auto-negotiation, would you please be able to try this
8.4 M2 development build? We have fixed a bug in this which was validated by a customer and ticket end user and you might be suffering from the same thing.
Kind regards,
Alban