I ran into exactly the same problem, but when I was killing Shiva VD. Also using Fire, Thunder, Light. But my overload happened right after Fire Maneuver while Overdrive was active. First time I've ever overloaded during Overdrive.

My attachments at the time:
Valoredge Header/Sharpshot frame
Optic Fiber 1/2
Auto-repair kit 4
Coiler 2
Attuner
Inhibitor 1/2
Speedloader 2
Magniplug 1/2
Turbo Charger 2
Steam Jacket


Attached: Screenshot of my combat log when the overload happened.