PHAT disconnects from WIFI approx 30 seconds after boot


The PHAT (firmware at v 0.5) on my PI zero disconnects from WIFI 30-40 seconds after boot up. Up till that point, I can PING and all is fine. After it disconnects, a ‘sudo iwlist wlan0 scan’ returns results and the PHAT still shows up in ‘ifconfig’ with its assigned IP address. But ‘ping’ stops working. Has anyone see that type of behavior before?