Tested this card with 12.0-RELEASE, 12.0-STABLE, 12.1-RELEASE, 12.1-STABLE and 13-CURRENT. The interface doesn't even appear, it's something related to the release of this card.
This motherboard isn't new, it's an Ivy Bridge one (Gigabyte GA-B75M-D3P).
re0: <RealTek 8168/8111 B/C/CP/D/DP/E/F/G PCIe Gigabit Ethernet> port 0xc300-0xc3ff mem 0xf2104000-0xf2104fff,0xf2100000-0xf2103fff at device 0.0 on pci3
re0: Using 1 MSI-X message
re0: Chip rev. 0x28800000
re0: MAC rev. 0x00300000
re0: attaching PHYs failed
device_attach: re0 attach returned 6
none3@pci0:3:0:0: class=0x020000 card=0xe0001458 chip=0x816810ec rev=0x04 hdr=0x00
vendor = 'Realtek Semiconductor Co., Ltd.'
device = 'RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller'
class = network
subclass = ethernet
Created attachment 214886 [details]
Here's a clean dmesg as a matter of reference.