I got new hap ax s after using hap ax2 for two years and the very same problem. Quick set page does not show the sane details, switching internet to automatic/dhcp just breaks configuration and makes modem unreachable without reboot. Despite DHCP server and NAT certainly works, they are not checked. It feels like Internet/Local Network do not match actual configuration.
PS: Reset to default config did not help. Also there are minor differences between hAP ax2 and hAP ax S, such as dhcp-default pool name, wifi interfaces, so reusing pieces of exported config is not straightforward.
