kernel: arpresolve: can't allocate llinfo for X.X.X.X on em0

[Noctur]

Noticed this in the system log... but everything seems to be working.

kernel: arpresolve: can't allocate llinfo for X.X.X.X on em0

em0 is the WAN port. I'm using a VPN. DNS leak and IP test point to the correct termination point. Is this truly an error or simply a message resulting from the use of a VPN? TIA