Effect of bad antenna design on chip behaviour
I believe that you are not providing enough current to the device. when the WiFi module start transmission it consumes x100mA in the range of 300-450mA. you should make sure to provide enough juice.
For further support you can find TI representative in here:https://e2e.ti.com/support/wireless_connectivity/simplelink_wifi_cc31xx_cc32xx/f/968

I hope my answer will help,
@NirNitzani