I am not familiar with MatNMR at all. However, since you data processes O.K. in SpinWorks (and presumably in TopSpin) then the data are O.K. I suspect that the problem is that you are not handling the TPPI data correctly. You need to use a real transform in F1. One way to do this is to expand the data into the real locations only, and insert zeros into the imaginary locations. Then apply the the standard fft algorithm and slightly different algorithm to extract the data from the array after transform. I'm not sure how you would do this in MatLab.