BNG dhcp-local-server and option 60

Hello again

We`ve got an interesting situation with option 60.

So i`ve got pc with pxe enabled that is connected to MX as subscriber.

And i got Discover with Option 60 and value of PXEClient:Arch:00000:UNDI:002001

Discover with pxe option-60After OS boots we got option 60 changed to MSFT 5.0

and next MX sends NAK.

The problem can be cleared with clear dhcp server binding  command.

So is it feature or a bug?

Can this be overriden?