I grew up hearing about the story of a wonder child in Jerusalem that was born knowing כל התורה כולה. The Gedolim of that era explained that he didn't receive the flick from the angel at birth to make one forget his learning that was taught to him in the mother's womb (see Niddah 30). I was wondering if anyone can validate this episode or provide any articles etc. that we're written about this very interesting story..
The Steipler Gaon, in his ספר חיי עולם סוף פרק יב (https://hebrewbooks.org/pdfpager.aspx?req=41473&st=&pgnum=23) brings the story and writes that he knew his knowledge from a previous Gilgul, not that the angel forgot to hit him. This is much more likely, as 1) an angel doesn't forget his task and 2) Rav Dessler explains the "hitting of the angel" metaphorically as the transition of the spiritual life of a foetus into the physical world. As such, no actual angel is involved.