I recently installed some cheap Type 1 switchbacks in my 2011 Sport. They stayed orange. Hmmmm... I paid some more money and bought some Type 2. They also stayed orange. I tested the LEDs on a bench. They were working fine. The inner two contacts are white, the outer two are amber. Time to get my multi-meter. I opened the hood and pulled the bulbs, and tested the socket. It turns out the voltage for the low filament (or in this case the amber color) never goes below 9V. When you put the turn signal on it alternates between 12V and 9V. When you turn the turn signal off, it goes back to 9V. 9V is not enough to turn the LEDs off, so they stay lit. 9V wont light the incandescent bulb, but it will light the LEDs. Hence, the white never get the signal to come on.
Aside from a solid state relay or a voltage regulator, I don't know how to solve the issue.