WiFi passphrase prompts

[Subhendu Ghosh <sghosh151 gmail com>]

I have seen this on F16 and on RHEL 6 -

Laptop is connected on wireless connection
Randomly, after ~18-24hrs, NM applet will prompt for a WPA passphrase.

NM is already configured with the passpharase.
When the system moves into range, it auto-connects without any prompts.

Seems like an issue with access to a store

Any suggested steps to debug?

-subhendu