This is a common problem when people switch the halogen bulbs from the indicators for LED bulbs. LEDs consume much less power than halogen bulbs. Therefore, you can choose from a wider range of colours with more brightness. And because they are of less power rating, LEDs offer little resistance in the circuit. This affects the flashing time of the indicators. So, the bulbs will flash much faster than before. Even Though that is not an issue in and of itself, this will cause the drivers to panic. You can avoid this by connecting an extra resistance in series while replacing a halogen bulb with an LED bulb.