What is WOT? With most of the light kits that I have seen white lights will go out soon after track power is off while the red lights stay on longer, sometimes much longer. I believe that is because white and blue LEDs operate at a higher voltage than red LEDs. I am not positive what the output voltage of the regulator is, but it must be higher than 3-3.3 volts or else there would not be a dropping resistor for each LED. Some light kits use a 3 volt regulator so only the red LEDs will need dropping resistors, red LEDs run at 2 volts.. Part of the problem may be that the diodes in the circuit have a voltage drop, but that should have been taken into account when the circuit was designed. Possibly the dropping resistors for the white and blue lights are not quite the right value. You have to use the resistors that are available, after you calculate the correct value you pick the closest available one, but it is safer to go for a higher value than a lower one. It might not be a bad idea to measure the voltage across one of the white LEDs first. If that is less than 3 volts the LED will be right at the point where it won't light. If you are willing to take a chance you could change the dropping resistor for one of the white LEDs to the next lowest value. You could then measure the voltage at that LED, after the dropping resistor, if the voltage is at least 3 but no more than 3.5 volts you would be good to go. If you run the LEDs even a little high you will shorten their life.
Here is an online calculator for selecting dropping resistors:
http://led.linear1.org/1led.wizIn order to use the calculator you would have to know what the output voltage of the regulator is. You would have to measure that after the diode. You would also have to know what the continuous amp rating of the LED is, if you don't know 30mA would be a good guess for white LEDs.
If the output of the regulator is 5 volts and you wanted 3.5 volts the dropping resistor would have to be 56 ohms, the color code for those is green, blue, black.