Often when using disruptor bombs exclusively (trying to figure them out) it seems - and I think this might be all the time - that a disruptor bomb ‘hit’ against a ship does not trigger the ‘shield flare’ animation.
It might be wise to just flash the whole shield white (or, make it whiter than usual and fade slowly back to normal, all over) when hit with a shield disruptor - they’re a particularly specific anti-shield weapon, after all, and it would make sense for shields to react differently when being hit by them.