It's due to the LEDs, because they have a much smaller draw current wise compared to your halogens. They operate on lower resistance values, so the CAN BUS system was triggered. It will stay lit until you either put the halogen bulbs back in, or until you attach resistors to each side in order to correct for the drop in resistance.
Attaching resistors then nullifies any benefit of drawing less power with LEDs compared to halogens.