Can't ping 192.168.1.1 but can see all other connected devices

I have the DSL version of the 6200 that exhibiting very flakey behavior.
I have two WNDR3700 in AP mode connected as a remote access points.
This normally works and I can wireless connect to either the 6200 or any of the 3700's and everything works.
Though often when you ask the 6200 for Attached device list it only finds 2, instead of the 30 or so of the wired devices connected.

But at times the two WNDR3700's connected stop providing internet access. You can log into them, and can ping all the other devices on the network, but you can't ping the 6200 itself (192.168.1.1). In order to see the other devices you have to be going through the 6200's ports. So you have to be succesfully connected to the 6200 to see the other devices, but the 192.168.1.1 part of it is not working or connected. If while this is happening you wirelessly connect to the 6200 directly, you can see 192.168.1.1, and also both WNDR3700's (but they don't show up as attached devices).

After a while, usually hours, the problem will fix itself and you can see 192.168.1.1 from the WNDR3700's and get to the internet from them. Often if you powercycle the 6200, the problem returns.
I've looked at wireshark while is is happening and not noticing any storms.

As a seperate issue, reserved DHCP doesn't seem to work on the DSL version of the 6200. Works on all my other 6200's

Any ideas would be appreciated. Never seen anything like this.