N600 WNDR3400V1 -- change security setting from WPA to WPA2

My iPad is starting to kick me off the home WiFI network after 5-10 minutes.  When I look at the WiFi setup on that device it presents me with a security recommendation of WPA2.  So I assume this is why I am getting kicked off when other devices at home are fine.

When I go into the router.net access, I do see where I can change the current WPA-PSK to WPA2-PSK or change to a combo of WPA-PSK/WPA2-PSK.

When I change both the 2.4GHz and 5GHz to either of the WPA2 options then click APPLY, the settings revert back to WPA-PSK.

What am I missing here?

Thanks, Matt