In Winbox same device with two MAC addresses - Why?

Hello,

I know its pretty simple and basic question to to group but… ever since I have uploaded MT from 6.35.x to 6.44 I see some devices shown in Winbox twice like this…
Screen Shot 2019-03-13 at 15.50.21.png
I assume it has something with discovery interfaces or a new setup. So, what should I choose in order to see all devices but only once.. or.. how can I setup discovery part in order to .. lets say only the router itself and none of the possible MT’s behind it?
Screen Shot 2019-03-13 at 15.51.19.png
tx

korg