Wiktionary
fall through the cracks
vb. (context idiomatic English) to be missed; to escape the necessary notice or attention
Usage examples of "fall through the cracks".
Things like Mahoney fall through the cracks and that's the way of the world.
If the army was cooperating with the National Guard, there would have to be a considerable amount of improvising and no doubt certain things would fall through the cracks.
I've passed the people who fall through the cracks, Richard: they sleep in shop doorways all down the Strand.