As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UPPER AND LOWER LED ANTICOLLISION BEACONS OCCASIONALLY CEASE OPERATING FOLLOWING BATTERY ENGINE START OR GPU ENGINE START. KING AIR MODEL B200GT, SERIAL BY-470 (BUNO 170744) AND ON. OPERATION MAY BE RESTORED BY CYCLING THE COCKPIT BEACON SWITCH (OFF AND BACK TO ON).