Yep, swap wiring. Had this issue with a whitewater i just restored. Had an LED that worked in other sockets but not the 2 insanity falls ones, after swapping drive transistors and boards and everything, i finally realised the factory wiring was back to front - didn't matter for an incandescent flasher, but it did for an LED. If it was wedge, you could turn the bulb around 180 degrees, but being bayonet, this makes no difference.