NAMD+MM_GBSA/PBSA for per residue energy decomposition

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Hi everynone,
For the MM_GBSA/PBSA calculation of NAMD version of trajectory , I used gmx_MMPBSA/example/psf_dcd/protein_protein for testing (Protein-protein - gmx_MMPBSA Documentation) , but I found that when adding &decomp (idecomp=2, dec_verbose=3, print_res=“within 100” ), the energy decomposition of all C-termius backbone of the amino acids is 0, I think this is very abnormal, so I have doubts about the overall energy calculation, has anyone met this problem, how should I solve it? Thanks a lot.

Best wishes,
Besty