I'll show you my router scenario. I have the main network running normally and the guest network using only the VPN. See the image below as I'm using it.
Every week, I noticed my Slate 7 would crash, and all connected devices would no longer be able to access the internet. Even if I restarted the Slate 7 or turned it off, when I turned it back on, the internet wouldn't work. I realized I needed to go to the VPN Dashboard and click "(OFF)," then do the same for "All Other Traffic." After that, the internet only worked again when I followed this exact order: Enable (ON) the VPN first, then enable (ON) "All Other Traffic" so that all devices could browse the internet again. Shouldn't this happen automatically when I turn on the router?
This could quite possibly be a race condition between WG & NTP. I'm quite sure the Slate 7 does not have a RTC. Further details/solution:
That's the real problem. You'd have to configure the Slate 7 to save its general logs to a USB disk. Do you have one you can use? I'll provide instructions once you do. You'll have to log into LuCI.
Wouldn't a future firmware update fix the issue? It's a recent firmware, so I imagine it might have bugs. Another thing I didn't mention is that when the router loses internet and I need to reboot it, if I don't follow this process of disabling the VPN and all other traffic, and then enabling the VPN first and then all other traffic, my Google TV Streamer 4K won't connect to the router. This happens after the Slate 7 reboots. The network appears saved on the Google TV Streamer, but when I click to connect, I get an error message. The only solution after the Slate 7 reboots is to disable everything and then enable the VPN first and then all other traffic, then the Google TV Streamer 4K can connect normally. What I don't understand is what the VPN policy has to do with the router's Wi-Fi connection?
It wouldn't surprise me if you've found a bug but you can't fix what isn't reproducible which is why logs are needed at a minimum.
Routing. The GL firmware makes use of custom scripts that dynamically change the routing tables/ordering in the base operating system OpenWrt Linux. The VPN 'interfaces' are also treated as any other network interface like the Wi-Fi's 2.4GHz or 5GHz radio, Ethernet ports. Those are all handled by the netifd daemon. Those actions (& more) appear in the logs, eg: logread -e netifd & logread.
I never needed to go thru the steps to get WAN & VPN connectivity you describe on my Slate AX — running v4.6.8 for example — regardless if 'cold booting' or just a 'reboot'.
I'm over-complicating things. GL staff are probably going to ask for your logs: GL GUI -> System -> Log -> [ Export Log ]. It's a tarball/archive so the contents are just a collection of UTF-8/LF text files. You should do that after a fresh/cold boot.