Gate level Simulation passes but design fails on target borad

I entered Matlab:

a =

[1.000000000000000, -1.999747125328010, 0.999748704265674];

>> b

b =

[ 0.999886916919553, -1.999747125328010, 0.999861787346121];

>> fvtool(b,a)

or use freqz(b,a)

I get a notch filter. its notch occurs at .001 of Fs 100000 = 100 Hz and this matches your description. However the attenuation is -.008db = .9991

As to your hex values it gives a completely different filter if I convert it on the basis of 2's complement...you need to check that