re fails diagnostics when heavy traffic

I've just figured this out.  At times, my re0 device would not show up
and I'd have to reboot once or twice before it worked.  Then I noticed I
couldn't get it at all and it turned out it was because I was streaming
some heavy data at the time.  Then I noticed it was failing because of
the following:

Aug 19 20:52:01 server kernel: rgephy0: <RTL8169S/8110S media interface> on miibus1
Aug 19 20:52:01 server kernel: rgephy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, 1000baseTX, 1000baseTX-FDX, auto
Aug 19 20:52:01 server kernel: re0: Ethernet address: 00:0c:76:e9:2c:58
Aug 19 20:52:01 server kernel: re0: diagnostic failed, failed to receive packet in loopback mode
Aug 19 20:52:01 server kernel: re0: attach aborted due to hardware diag failure

Anything I can do to assist in fixing this please let me know.  It has
been a frustrating issue.

Cheers,
Sean