There is a program called “repeater manager”, which tries to find available SSIDs and connect to it. Once there is no SSID available, it will just disable the repeater.
So when you turn off wds, the 2nd router cannot find its buddy and turn off the repeater. But if you just wait for more time, it will connect again.
To connect repeater immediately, here is what you should do:
comment out gl_health in /etc/rc.local and reboot the router.
After you doing this, if the first router is turned off, the 2nd router will not broadcast wifi.