lost IP

The First problem:
Firmware 1.4.0
So I want to connect one CPE to another AP. My steps:
-Chanding AP name in CPE
-Pushing save button
-CPE lost connection and when it connects to new AP the WAN IP address is not reachable till it will be hard rebooted.
The Second problem:
Firmware 1.4.0
We use static and NAT on our CPEs. During installation after changes and reboot in MONITOR-NETWORK STATUS I see “–” instead of WAN IP address and no internat access. In CONFIGURE-NETWORK there is necessary WAN IP .
Is it a bug of 1.4.0?