Kernel arp message, very minor

[brcisna]

Hello All,

Hardware Info:

Two new builds of pfSense-2.1.4-RELEASE. (amd64)
squid
squidGaurd
lightsquid

New ISP providing a new fiber line at both buildings.

Both pfSense machines are working great after doing somef tweaking on the one that is running three lan nics to provide three lan subnets segmented at one of the two school buildings.
We previously run both 1.2.3 & 2.0.1 pfSense

Error:

A very minor message that appears in both of the machines message logs about every 10 minutes is
kernel: arp: 123.123.123.123 moved from 00:15:17:dc:00:00 to 40:55:39:13:00:00 on em0

After checking ,of course,  this is the actual pfSense WAN mac then shows as it's IP WAN  being moved to the Cisco managed switch that is the fiber converter that resides in front of the pfSense router, that our new ISP provided at each building.
I am going to call the ISP and ask if the WAN gateway port on their managed switch is running in bridged mode,and if so I would guess this is expected behavior on part of the pfSense router.

Anyone ever run into this scenario?

Thank You,
Barry