WiFI_KIT_8 Soft WDT reset

Just moved my TSC3472 I2C color sensor program to the WiFi_Kit_8 (from a MEGA). Not using Wifi, just simple I2C to the sensor. I2C is not the issue. I print a menu of user topics ( i.e read and display registers). The user input routine waits for a to exit. If I loop on…

c= Serial.read();

I get a Soft WDT reset. If I do a

while(!serial.available());

prior to the serial read loop I get no WDT. It looks like it doesn’t like to read the serial if there are no characters available. This shouldn’t be necessary. I’d just like to understand what I missed here.