They should reset to what they are expected. Then ping each machine, and check the arp tables again. I think maybe something is out of whack from when you were playing with arp spoof, you should probably reset the MAC on the VM's adapters. If doing no attacks at all before even doing arp spoof, and just checking arp -a, and they look to be wrong, I'd say reboot your VM and make sure all network settings are back to normal, no ipfoward set in the VM too. What I mean, is that when using the onboard wireless interface as the vbox/vmware bridged interface, then when I'm 'arp -a' from another physical machine (on the same network), I see that the MAC of host PC (on which kali vm is) AND the kali VM are same (equals to the host PC MAC). And it's not the attacking wireless interface, it's just the one used for bridging. and they vary by virtual product, ie: vbox, vs vmware, vs qemu, etc. Virtual machines are great, they just don't do everything 100% as expected. More than likely, the wifi adapter also doesn't do injection and monitor mode properly under vbox, which has also been my experience, and why I tend ot use wifi stuff on my laptop, or Vmware which sort of works for most of my adapters. All else fails, use native hardware, or try VMware to see if you can get around the issue for the wifi adapter. Bridged to the physical network and getting DHCP from the actual home router is what you ideally want to test with, but I have a feeling for wifi, it's not doing this physical dongle setup properly in VBox. Can try changing the adapter settings when the VM is off to things like NAT or Bridge, althogh NAT will prevent ARP attacks(in theory) since they need to be on the same subnet, where NAT will divide the network(s). VBox, from the sounds of it, passes the device by proxy and not as a physical device attached over USB, so seems to me it's cloning the host machines MAC and just passing it across.

Best thing is run on native hardware, test, works, then work out the kinks on the VM side since that seems to be the issue, not Kali, but the virtual machine architecture. On VBox, the wifi, for whatever reason, never seems to work properly(for me anyway) but I chalk this up to the virtual machine side, and not a Kali issue. Was this uses only in VBox before, or was it Vmware? Vmware will pass the physical adapter mac.

Arpspoof kali in virtualbox