Re: Cascading Filters
Well I guess you did mix up when writing your post, the LPF has a Fc=257MHz while the HPF has a Fc=2MHz.
Either that or your design is actually a band stop filter instead of a band pass.
As for your question, I agree with what Safwat has just mentioned about the loading effect between both filters. Cascading 2 filters will surely alter the characteristics of each filter operating individually since the load resistance of the first filter is the input impedance of 2nd stage, while the source resistance of 2nd filter is turned into the output impedance of the 1st filter.
Try resimulating using appropriate load and source impedances and keep us updated, maybe my opiniong is wrong, but then only you can prove me either right or wrong.
Salam for now