Different MAC Address shown in router?

When I look in my phone app, the listed MAC Address for my HomeBase (with Wireless Doorbell) matches that on the bottom of the device;
However in my router, it shows a different MAC address for the LAN IP that the Homebase is connected
???
Why is that?
(everything works great, just an anomaly I noticed as I was assigning recognizable device names in my list of Router Connections)