Core issue
he error message can looks like this:
%FIB-4-FIBXDRINV:Invalid format. [chars]
%FIB-DFC5-4-FIBXDRINV: Invalid format. [chars]
This means that an internal software error has occurred.
In a scenario, this message can appear after a virtual LAN (VLAN) interface is disabled while servers on a couple of networks are moved to another location. The networks on this pair of switches are disabled and moved to another pair of switches.
Hence, in this scenario, the message means that the Hot Standby Router Protocol (HSRP) MAC address still remains in the adjacency table when the VLAN interface is deleted while still in the administratively up state. The message can be avoided, if the VLAN interface is first put into an administratively down state and then deleted.
Resolution
Either way, the message itself is harmless and is often not indicative of an actual problem.
Open a service request with Cisco Technical Support with the TAC Service Request Tool for more assistance.
