Hello
since the 6.29 (6.27 is unstable with the Hex RB750) we encounter systematically Auto negociation problem with device connected which have intel network card.
For an unknown reason, it seems to be present just for the port 3 to 5.
The port stay shutdown when we connect the intel network card
This is the same with all routeurOS (as the last 6.32 RC5)
any help could be appreciated 
Best regards
MK