This is an odd one, but I'm able to consistently reproduce it and it seems like tailscale is the cause.

I have a Pixel 7 phone with tailscale set as the vpn. I'm not using an exit node. When I go though the subway and loose cellular connection, internet won't work once my phone re-connects to the cell tower. It shows full bars but web pages don't load. Rebooting the phone fixes the problem.

The odd thing is this only happens if I have tailscale enabled. If I disconnect from tailscale, going through subway tunnels works fine - it reconnects once I'm out of the tunnel and I don't need to reboot the phone.