I have been debugging a super odd issue an issue with a HP Elitebook 840 G8 or newer and any of the new HP device fleet for over a month. And the colleagues I am assisting have been trying to find the root cause for months. HP have come back with a fix but I am interested to know if this problem exists on other non-HP hardware as their theory was it should as it is an underly Windows 10/11 Modern Standby issue.
If you first you need to have a modern Intel Gen 10 or newer laptop with Standby (S0 Low Power Idle) Network Connected. If it says Standby S3 then this issue doesn't occur.
Then if you are using the Cisco AnyConnect (or Fortigate VPN, as both SSL VPNs have this issue) and first you ping your hostname when off then VPN, then ping it again when on the VPN. If this was working as expected then your computer should resolve the IP address allocated via the VPN tunnel. But what happens is the IP address of your home network is resolved and you get a General Failure as you can't contact your internal adapter when the VPN tunnel is up.
If you then disable on the adapter you are using the "NS offload" or similar setting then the ping does work as expected resolving the hostname the IP address of the tunnel.
Anyone else using non HP hardware that has the above Standby S0 powercfg. Ideally already have a SSL VPN either Cisco or Fortigate and could quickly test this. Or I can message anyone offline with a test client and VPN endpoint to test with.