Forgiving the long title, but If a ship is shielded and is struck by weapons fire, for the duration that the shields play the "flared up" animation from being hit, the Full-bright or "Light mode" from the ADV build menu will deactivate temporarily.
Recreate: spawn in shielded ship,
Hop into ship
enter Build mode, Activate the lightmode from Advanced Build,
Spawn in pirates, Allow pirates to fire upon shielded vessel you are piloting.
Watch as on a successful hit, Lighten mode disables itself in various parts of the ship
I am unsure if this is just a side effect of the game engine, or is a bug, but Ill post it as such just in case
another gif in a more controlled environment: