Hello wb,
packets from .2 arrive at interface 'intel i218-v' by ethernet cable and are passed to bound 'VirtualBox Bridged Networking Driver'. ( And "behind" this driver emulated NIC for virtual machine .10 is implemented. )
Packets from .1 reach interface via bound 'internet protocol version 4' and are not passed to 'VirtualBox Bridged Networking Driver'.
'.2' is also a 'win 7 pro 64bit' system with an 'intel 82567lm' - but I can reproduce the behavior with any cable-separated node and any virtualized guest - amongst others a bootable linux '.iso'.
cu - Stefan