I'm receiving the same thing here, but still do not have a
resolution. Look at them closely to see if other MAC are also
reporting the same dup as well on this machine.
As far as HA is concerned it will only report against traffic on
that box. As the IP address ports over I would be curious to
see if they start logging on the other node if you executed a
fall over to the second node.
As far as issues, a duplicate IP address being reported usually
creates problems that (unfortunately) will prove themselves out
in time, but I have not identified any issues with the current
duplicate IPs being report, and it has been going on for some
time.