Nolan had a poor memory, as is evidenced in the YouTube interview.
There are lots of inconsistencies and I would suggest they do not all just magically fall on Nolan
When shown an FBI FD-302 dated November 23,1963 (Agency File Number 000919, Record # 180-l 0090-10270), she felt it was inaccurate in two respects: it quotes her as turning over ?the metal fragment (singular),? whereas she is positive it was multiple fragments - it says she turned over the fragment to a Texas State Trooper, whereas she recalls turning it over to plainclothes Federal agents who were either FBI or Secret Service.
To corroborate her denial, Bell suggested that they look at the receipt she was required to fill out, which she had passed on to Parkland administrator, Jack Price. Of course, that receipt had to have been confiscated by the FBI, since it was critical to confirming the chain of custody. This is more from MD184,
She independently recalled filling out a receipt on 1l/22/63 for the fragments, on half-page sized paper with red lettering in the letterhead, which was signed for by one of two men in civilian clothes (whom she thought were Federal agents) who accepted the fragments. She said she personally delivered the original of this receipt to Parkland Hospital Administrator Jack Price. (ARRB staff promised to try to locate this document, and promised that if located, we would mail her a photocopy for verification purposes.)
But according to the National Archives, there is no record of the ARRB ever finding that receipt and the Archives were not able to find it either. So Bell's receipt, which would have confirmed the name of at least one of the men she gave the envelope to, and which had to have been taken by the FBI, seems to have evaporated.
So there is your missing receipt