Hi Pavan,
you are right that there is a discrepancy in the I/O:
NetCDF files have a grid of size 2(N/3) for padded fields.
HDF5 files have a grid of size (2N)/3 for padded fields.
Since these are integer operations they may differ. Although this changes the physical representation of the FlowField, the spectral data is the same for both of them because it affects a mode which is zero. Thus, it is not really a bug but I agree that it is confusing if you look at the interpolated data in physical representation.
I created a PR to adjust the HDF5 output:
Best regards,
Florian