Do you use pull-down resistors on those 2 pins?
When the MCU resets, all i/o pins go into Tri-State (High Impedance) and then default to input pins (Also high input resistance) until your sketch defines them as output pins.
Using a resistor (one for each pin, 10K/47K or so) to ground will make sure the pin stays LOW unless explicitly driven HIGH by the output.
Hope this helps,
Guido