Yes, this is more ore less "normal". You are hitting CSCtj81255 (at least if you´re using 1121 appliance). The secondary MAC Address is the BMC (Baseboard Management Controller) which is by default activated and is getting an IP Address via DHCP by default.
Deactivating the BMC is not possible, but there is a workaround which worked quite well in our implementation.
Edit the BMC settings in the BIOS to disable DHCP and set a static IP Address in a range which does not intervene with your IP Address layout in your network.
Login to the FXOS chassis manager.
Direct your browser to https://hostname/, and log-in using the user-name and password.
Go to Help > About and check the current version:
Check the current version availa...
We have configured the outside and inside Interface with official ipv6 adresses, set a default route on outside Interface to our router, we also have definied a rule , which also gets hits, to permit tcp from inside Interface to any6.
In Syslog I also se...