When TXP and TXN are unconnected, no DRC warning is issued. Additionally, no DRC warning is issued when RXP and RXN are connected to incorrect pins.
DRC checking on the TXP, TXN, RXP, and RXN pins is limited. You must verify that the pins are in the correct locations through use of the data sheet and the pad report.
This functionality will be enhanced in a future design tools release.