I am also having this exact issue. Just with the 2.5g port. The port functions for an undefined period of time then the blue light goes off, the connection stalls, then it drops to 1g. Even on 1g the 2.5g port stalls data. Moving the ethernet cable over to a 1g port fixes all connectivity issues, but at the slower 1g speed. Multiple factory resets done. Going to try disabling wireless radio and trying again. Support tickets have proven useless. I was given the option to replace it, but I'm not paying to get a replacement for a defect and it certainly seems to be firmware related.
