What is your Network threat model?

I don’t follow. How do they conclude “a VPN service is not working properly” when localhost traffic isn’t even sent to it?

One could definitely say that Android’s VPN services won’t block localhost traffic… but to say that VPN services don’t work properly when Android itself isn’t routing localhost traffic to it (among other bits of traffic as noted in my previous reply), is bit of a head-scratcher. Or, may be I misunderstand.

Though, if Android’s Block connections without VPN toggle is turned ON, I’d want hyper security-focused Android forks like Graphene, if not AOSP itself, to block ALL traffic not flowing through VPN services.