A rare error when parsing huge integers

[axiopost]

Hi,
I am writing a faster parser function than the original one and while testing it I raised up an error that may be reproduce with this code:

procedure AParsingError;
var
  N,M : BigInteger;
  R : IRandom;
begin
  R := TDelphiRandom.Create(-332888001);
  N := BigInteger.Create(Random(100)*1000, R);
  BigInteger.Base := 12;
  M := BigInteger.Parse(N.ToString);
  if (N<>M) then raise Exception.Create('Parsed value differs from the original!');
end;

The N.ToString and M.ToString differs per the digits from positions 1983 to 1992 (probabely a Limb).
In attached file uBadValue.zip
there is a unit file embeding the value produced by the random generator (18250 hex-digits long), just in case.

Best regards,
F. MARQUES